uboot-imx

efi_loader: use EFI_PAGE_SIZE instead of 4096

We should use constant EFI_PAGE_SIZE instead of 4096 where the
coding relies on 4096 being EFI_PAGE_SIZE.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>