uboot-imx

x86: baytrail: Support operation as an EFI payload

Disable a few things which interfere with the EFI init. This allows the
Minnowboard MAX to boot into EFI, load a U-Boot payload then boot to the
U-Boot prompt.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>