ubifs: Reject unsupported ioctl flags explicitly

commit 2fe8b2d5578d7d142982e3bf62e4c0caf8b8fe02 upstream.

Reject unsupported ioctl flags explicitly, so the following command
on a regular ubifs file will fail:
	chattr +d ubifs_file

And xfstests generic/424 will pass.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>