xfs: remove xfs_rmap_ag_owner and friends

xfs: remove xfs_rmap_ag_owner and friends

Source kernel commit: 7280fedaf3a0f9097c0621c7d5b35849954d7f54

Owner information for static fs metadata can be defined readonly at
build time because it never changes across filesystems.  This enables us
to reduce stack usage (particularly in scrub) because we can use the
statically defined oinfo structures.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>