This patch adds basic support for the Armada 375. Please note that
currently the SerDes and DDR3 init code for the A375 is not
included / enabled. This will be done in a later, follow-up patch.

Right now, this A375 mainline U-Boot can only be used by chainloading
it via the original Marvell U-Boot. This can be done via this
command:

=> tftpboot 00800000 a375/u-boot-dtb.bin;go 00800000

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Luka Perkov <luka.perkov@sartura.hr>