xfs: fix the comment of xfs_ifree_cluster()

Signed-off-by: NZhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Reviewed-by: NMark Tinguely <tinguely@sgi.com>
Signed-off-by: NBen Myers <bpm@sgi.com>

fs/xfs/xfs_inode.c

@@ -2095,7 +2095,7 @@ xfs_iunlink_remove(
 }
 
 /*
- * 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.
  */