kconfig: add blank Kconfig files

This would be useful to start moving various config options.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

Kconfig

@@ -91,7 +91,7 @@ config SYS_EXTRA_OPTIONS
 	depends on !SPL_BUILD
 	help
 	  The old configuration infrastructure (= mkconfig + boards.cfg)
-	  provided the extra options field. It you have something like
+	  provided the extra options field. If you have something like
 	  "HAS_BAR,BAZ=64", the optional options
 	    #define CONFIG_HAS
 	    #define CONFIG_BAZ	64
@@ -103,3 +103,13 @@ config SYS_EXTRA_OPTIONS
 endmenu		# Boot images
 
 source "arch/Kconfig"
+
+source "common/Kconfig"
+
+source "net/Kconfig"
+
+source "drivers/Kconfig"
+
+source "fs/Kconfig"
+
+source "lib/Kconfig"

common/Kconfig

+menu "Command line interface"
+	depends on !SPL_BUILD
+
+endmenu

drivers/Kconfig

+menu "Device Drivers"
+
+source "drivers/core/Kconfig"
+
+source "drivers/pci/Kconfig"
+
+source "drivers/pcmcia/Kconfig"
+
+source "drivers/mtd/Kconfig"
+
+source "drivers/block/Kconfig"
+
+source "drivers/misc/Kconfig"
+
+source "drivers/net/Kconfig"
+
+source "drivers/input/Kconfig"
+
+source "drivers/serial/Kconfig"
+
+source "drivers/tpm/Kconfig"
+
+source "drivers/i2c/Kconfig"
+
+source "drivers/spi/Kconfig"
+
+source "drivers/gpio/Kconfig"
+
+source "drivers/power/Kconfig"
+
+source "drivers/hwmon/Kconfig"
+
+source "drivers/watchdog/Kconfig"
+
+source "drivers/video/Kconfig"
+
+source "drivers/sound/Kconfig"
+
+source "drivers/usb/Kconfig"
+
+source "drivers/dfu/Kconfig"
+
+source "drivers/mmc/Kconfig"
+
+source "drivers/rtc/Kconfig"
+
+source "drivers/dma/Kconfig"
+
+source "drivers/crypto/Kconfig"
+
+endmenu

fs/Kconfig

+#
+# File system configuration
+#
+
+menu "File systems"
+
+source "fs/ext4/Kconfig"
+
+source "fs/reiserfs/Kconfig"
+
+source "fs/fat/Kconfig"
+
+source "fs/jffs2/Kconfig"
+
+source "fs/ubifs/Kconfig"
+
+source "fs/cramfs/Kconfig"
+
+endmenu

lib/Kconfig

+menu "Library routines"
+
+endmenu

net/Kconfig

+#
+# Network configuration
+#
+
+menuconfig NET
+	bool "Networking support"
+
+if NET
+
+endif   # if NET