uboot-imx

ARM: ts4800: add basic board support

This commit adds basic support including:
MMC, Serial console, TS4800 watchdog

The config use CONFIG_SKIP_LOWLEVEL_INIT as U-boot is used as a second
stage bootloader.

Signed-off-by: Lucile Quirion <lucile.quirion@savoirfairelinux.com>
signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Cc: Stefano Babic <sbabic@denx.de>