xfs: do not use xfs_mod_incore_sb for per-cpu counters

Export xfs_icsb_modify_counters and always use it for modifying
the per-cpu counters.  Remove support for per-cpu counters from
xfs_mod_incore_sb to simplify it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 6a1edb1..a7c116e 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -596,7 +596,8 @@
 		 * the extra reserve blocks from the reserve.....
 		 */
 		int error;
-		error = xfs_mod_incore_sb(mp, XFS_SBS_FDBLOCKS, fdblks_delta, 0);
+		error = xfs_icsb_modify_counters(mp, XFS_SBS_FDBLOCKS,
+						 fdblks_delta, 0);
 		if (error == ENOSPC)
 			goto retry;
 	}