xfs: fix the comment of xfs_extent_busy_update_extent()

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_extent_busy.c

@@ -147,7 +147,7 @@ xfs_extent_busy_search(
  * extent.  If the overlap covers the beginning, the end, or all of the busy
  * extent, the overlapping portion can be made unbusy and used for the
  * allocation.  We can't split a busy extent because we can't modify a
- * transaction/CIL context busy list, but we can update an entries block
+ * transaction/CIL context busy list, but we can update an entry's block
  * number or length.
  *
  * Returns true if the extent can safely be reused, or false if the search