Almost all identifiers use the FS_* namespace, so rename the missing few
XFS_* ones to FS_* as well.  Without this some people might get upset
about having too many XFS names in generic code.
Acked-by: NSteven Whitehouse <swhiteho@redhat.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJan Kara <jack@suse.cz>