xfs: fix the comment of xfs_iroot_realloc()

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_fork.c

@@ -473,7 +473,7 @@ xfs_iread_extents(
  *
  * The caller must not request to add more records than would fit in
  * the on-disk inode root.  If the if_broot is currently NULL, then
- * if we adding records one will be allocated.  The caller must also
+ * if we are adding records, one will be allocated.  The caller must also
  * not request that the number of records go below zero, although
  * it can go to zero.
  *