xfs: skip scrub xref if corruption already noted

Don't bother looking for cross-referencing problems if the metadata is
already corrupt or we've already found a cross-referencing problem.
Since we added a helper function for flags testing, convert existing
users to use it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c
index 3f8fd10..e5a4611 100644
--- a/fs/xfs/scrub/bmap.c
+++ b/fs/xfs/scrub/bmap.c
@@ -174,7 +174,7 @@ xfs_scrub_bmap_xref_rmap(
 	unsigned long long		rmap_end;
 	uint64_t			owner;
 
-	if (!info->sc->sa.rmap_cur)
+	if (!info->sc->sa.rmap_cur || xfs_scrub_skip_xref(info->sc->sm))
 		return;
 
 	if (info->whichfork == XFS_COW_FORK)