xfs: fix the comment of xfs_ifree_cluster()

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 8750cdb..e3d7538 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2095,7 +2095,7 @@
 }
 
 /*
- * A big issue when freeing the inode cluster is is that we _cannot_ skip any
+ * A big issue when freeing the inode cluster is that we _cannot_ skip any
  * inodes that are in memory - they all must be marked stale and attached to
  * the cluster buffer.
  */