uboot-imx

arm: baltos: move the board to CONFIG_BLK

Use DM for both MMC and USB subsystems and use dedicated DTS
for U-Boot configuration.

Disable SPL support for GPIO and remove EVMSK leftover for
DDR power control via GPIO.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>