pnfs: fix incorrect comment in destroy_lseg

Comment references get_layout_hdr_locked, which never existed in
submitted code.
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/pnfs.c

@@ -225,7 +225,7 @@ destroy_lseg(struct kref *kref)
 
 	dprintk("--> %s\n", __func__);
 	NFS_SERVER(ino)->pnfs_curr_ld->free_lseg(lseg);
-	/* Matched by get_layout_hdr_locked in pnfs_insert_layout */
+	/* Matched by get_layout_hdr in pnfs_insert_layout */
 	put_layout_hdr(ino);
 }