[readdir] ->readdir() is gone

everything's converted to ->iterate()

Signed-off-by: Al Viro <[email protected]>
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 85a4a03..206a1bd 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -448,3 +448,6 @@
 --
 [mandatory]
 	vfs_readdir() is gone; switch to iterate_dir() instead
+--
+[mandatory]
+	->readdir() is gone now; switch to ->iterate()