[readdir] ->readdir() is gone

everything's converted to ->iterate()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Documentation/filesystems/porting

@@ -448,3 +448,6 @@ in your dentry operations instead.
 --
 [mandatory]
 	vfs_readdir() is gone; switch to iterate_dir() instead
+--
+[mandatory]
+	->readdir() is gone now; switch to ->iterate()