uboot-imx

efi_net: return EFI_UNSUPPORTED where appropriate

U-Boot does not implement all functions of the simple network
protocol. The unimplemented functions return either of
EFI_SUCCESS and EFI_INVALID_PARAMETER.

The UEFI spec foresees to return EFI_UNSUPPORTED in these cases.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Alexander Graf <agraf@suse.de>