uboot-imx

efi: stub: Pass EFI system table address to U-Boot payload

This updates the EFI stub codes to pass UEFI BIOS's system table
address to U-Boot payload so that U-Boot can utilize it.

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