xfs: reject unknown xattri log item operation flags during recovery

Make sure we screen the op flags field of recovered xattr intent log
items to reject flag bits that we don't know about.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>