efi_loader: eliminate efi_uninstall_protocol_interface_ext

As we now have EFI_CALL there is no need for separate
functions efi_uninstall_protocol_interface_ext and
efi_uninstall_protocol_interface.

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