uboot-imx

efi_loader: Always allocate the highest available address

Some EFI applications (grub2) expect that an allocation always returns
the highest available memory address for the given size.

Without this, we may run into situations where the initrd gets allocated
at a lower address than the kernel.

This patch fixes booting in such situations for me.

Signed-off-by: Alexander Graf <agraf@suse.de>