kconfig: add board Kconfig and defconfig files

This commit adds:
 - arch/${ARCH}/Kconfig
    provide a menu to select target boards
 - board/${VENDOR}/${BOARD}/Kconfig or board/${BOARD}/Kconfig
    set CONFIG macros to the appropriate values for each board
 - configs/${TARGET_BOARD}_defconfig
    default setting of each board

(This commit was automatically generated by a conversion script
based on boards.cfg)

In Linux Kernel, defconfig files are located under
arch/${ARCH}/configs/ directory.
It works in Linux Kernel since ARCH is always given from the
command line for cross compile.

But in U-Boot, ARCH is not given from the command line.
Which means we cannot know ARCH until the board configuration is done.
That is why all the "*_defconfig" files should be gathered into a
single directory ./configs/.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/arc/Kconfig

+menu "ARC architecture"
+	depends on ARC
+
+config SYS_ARCH
+	string
+	default "arc"
+
+choice
+	prompt "Target select"
+
+config TARGET_TB100
+	bool "Support tb100"
+
+config TARGET_ARCANGEL4
+	bool "Support arcangel4"
+
+config TARGET_ARCANGEL4_BE
+	bool "Support arcangel4-be"
+
+config TARGET_AXS101
+	bool "Support axs101"
+
+endchoice
+
+source "board/abilis/tb100/Kconfig"
+source "board/synopsys/Kconfig"
+source "board/synopsys/axs101/Kconfig"
+
+endmenu

arch/avr32/Kconfig

+menu "AVR32 architecture"
+	depends on AVR32
+
+config SYS_ARCH
+	string
+	default "avr32"
+
+choice
+	prompt "Target select"
+
+config TARGET_ATNGW100
+	bool "Support atngw100"
+
+config TARGET_ATNGW100MKII
+	bool "Support atngw100mkii"
+
+config TARGET_ATSTK1002
+	bool "Support atstk1002"
+
+config TARGET_ATSTK1003
+	bool "Support atstk1003"
+
+config TARGET_ATSTK1004
+	bool "Support atstk1004"
+
+config TARGET_ATSTK1006
+	bool "Support atstk1006"
+
+config TARGET_FAVR_32_EZKIT
+	bool "Support favr-32-ezkit"
+
+config TARGET_GRASSHOPPER
+	bool "Support grasshopper"
+
+config TARGET_MIMC200
+	bool "Support mimc200"
+
+config TARGET_HAMMERHEAD
+	bool "Support hammerhead"
+
+endchoice
+
+source "board/atmel/atngw100/Kconfig"
+source "board/atmel/atngw100mkii/Kconfig"
+source "board/atmel/atstk1000/Kconfig"
+source "board/earthlcd/favr-32-ezkit/Kconfig"
+source "board/in-circuit/grasshopper/Kconfig"
+source "board/mimc/mimc200/Kconfig"
+source "board/miromico/hammerhead/Kconfig"
+
+endmenu

arch/blackfin/Kconfig

+menu "Blackfin architecture"
+	depends on BLACKFIN
+
+config SYS_ARCH
+	string
+	default "blackfin"
+
+choice
+	prompt "Target select"
+
+config TARGET_BCT_BRETTL2
+	bool "Support bct-brettl2"
+
+config TARGET_BF506F_EZKIT
+	bool "Support bf506f-ezkit"
+
+config TARGET_BF518F_EZBRD
+	bool "Support bf518f-ezbrd"
+
+config TARGET_BF525_UCR2
+	bool "Support bf525-ucr2"
+
+config TARGET_BF526_EZBRD
+	bool "Support bf526-ezbrd"
+
+config TARGET_BF527_AD7160_EVAL
+	bool "Support bf527-ad7160-eval"
+
+config TARGET_BF527_EZKIT
+	bool "Support bf527-ezkit"
+
+config TARGET_BF527_SDP
+	bool "Support bf527-sdp"
+
+config TARGET_BF533_EZKIT
+	bool "Support bf533-ezkit"
+
+config TARGET_BF533_STAMP
+	bool "Support bf533-stamp"
+
+config TARGET_BF537_MINOTAUR
+	bool "Support bf537-minotaur"
+
+config TARGET_BF537_PNAV
+	bool "Support bf537-pnav"
+
+config TARGET_BF537_SRV1
+	bool "Support bf537-srv1"
+
+config TARGET_BF537_STAMP
+	bool "Support bf537-stamp"
+
+config TARGET_BF538F_EZKIT
+	bool "Support bf538f-ezkit"
+
+config TARGET_BF548_EZKIT
+	bool "Support bf548-ezkit"
+
+config TARGET_BF561_ACVILON
+	bool "Support bf561-acvilon"
+
+config TARGET_BF561_EZKIT
+	bool "Support bf561-ezkit"
+
+config TARGET_BF609_EZKIT
+	bool "Support bf609-ezkit"
+
+config TARGET_BLACKSTAMP
+	bool "Support blackstamp"
+
+config TARGET_BLACKVME
+	bool "Support blackvme"
+
+config TARGET_BR4
+	bool "Support br4"
+
+config TARGET_CM_BF527
+	bool "Support cm-bf527"
+
+config TARGET_CM_BF533
+	bool "Support cm-bf533"
+
+config TARGET_CM_BF537E
+	bool "Support cm-bf537e"
+
+config TARGET_CM_BF537U
+	bool "Support cm-bf537u"
+
+config TARGET_CM_BF548
+	bool "Support cm-bf548"
+
+config TARGET_CM_BF561
+	bool "Support cm-bf561"
+
+config TARGET_DNP5370
+	bool "Support dnp5370"
+
+config TARGET_IBF_DSP561
+	bool "Support ibf-dsp561"
+
+config TARGET_IP04
+	bool "Support ip04"
+
+config TARGET_PR1
+	bool "Support pr1"
+
+config TARGET_TCM_BF518
+	bool "Support tcm-bf518"
+
+config TARGET_TCM_BF537
+	bool "Support tcm-bf537"
+
+endchoice
+
+source "board/bct-brettl2/Kconfig"
+source "board/bf506f-ezkit/Kconfig"
+source "board/bf518f-ezbrd/Kconfig"
+source "board/bf525-ucr2/Kconfig"
+source "board/bf526-ezbrd/Kconfig"
+source "board/bf527-ad7160-eval/Kconfig"
+source "board/bf527-ezkit/Kconfig"
+source "board/bf527-sdp/Kconfig"
+source "board/bf533-ezkit/Kconfig"
+source "board/bf533-stamp/Kconfig"
+source "board/bf537-minotaur/Kconfig"
+source "board/bf537-pnav/Kconfig"
+source "board/bf537-srv1/Kconfig"
+source "board/bf537-stamp/Kconfig"
+source "board/bf538f-ezkit/Kconfig"
+source "board/bf548-ezkit/Kconfig"
+source "board/bf561-acvilon/Kconfig"
+source "board/bf561-ezkit/Kconfig"
+source "board/bf609-ezkit/Kconfig"
+source "board/blackstamp/Kconfig"
+source "board/blackvme/Kconfig"
+source "board/br4/Kconfig"
+source "board/cm-bf527/Kconfig"
+source "board/cm-bf533/Kconfig"
+source "board/cm-bf537e/Kconfig"
+source "board/cm-bf537u/Kconfig"
+source "board/cm-bf548/Kconfig"
+source "board/cm-bf561/Kconfig"
+source "board/dnp5370/Kconfig"
+source "board/ibf-dsp561/Kconfig"
+source "board/ip04/Kconfig"
+source "board/pr1/Kconfig"
+source "board/tcm-bf518/Kconfig"
+source "board/tcm-bf537/Kconfig"
+
+endmenu

arch/m68k/Kconfig

+menu "M68000 architecture"
+	depends on M68K
+
+config SYS_ARCH
+	string
+	default "m68k"
+
+choice
+	prompt "Target select"
+
+config TARGET_M52277EVB
+	bool "Support M52277EVB"
+
+config TARGET_M5235EVB
+	bool "Support M5235EVB"
+
+config TARGET_COBRA5272
+	bool "Support cobra5272"
+
+config TARGET_EB_CPU5282
+	bool "Support eb_cpu5282"
+
+config TARGET_TASREG
+	bool "Support TASREG"
+
+config TARGET_M5208EVBE
+	bool "Support M5208EVBE"
+
+config TARGET_M5249EVB
+	bool "Support M5249EVB"
+
+config TARGET_M5253DEMO
+	bool "Support M5253DEMO"
+
+config TARGET_M5253EVBE
+	bool "Support M5253EVBE"
+
+config TARGET_M5272C3
+	bool "Support M5272C3"
+