xfs: refactor XFS_QMOPT_DQNEXT out of existence

There's only one caller of DQNEXT and its semantics can be moved into a
separate function, so create the function and get rid of the flag.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/scrub/quota.c

@@ -268,8 +268,7 @@ xfs_scrub_quota(
 		if (xfs_scrub_should_terminate(sc, &error))
 			break;
 
-		error = xfs_qm_dqget(mp, NULL, id, dqtype, XFS_QMOPT_DQNEXT,
-				&dq);
+		error = xfs_qm_dqget_next(mp, id, dqtype, &dq);
 		if (error == -ENOENT)
 			break;
 		if (!xfs_scrub_fblock_process_error(sc, XFS_DATA_FORK,