[GENETLINK]: Add cmd dump completion.

Remove assumption that generic netlink commands cannot have dump
completion callbacks.

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index 7fd131c..adff4c8 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -53,6 +53,7 @@
  * @policy: attribute validation policy
  * @doit: standard command callback
  * @dumpit: callback for dumpers
+ * @done: completion callback for dumps
  * @ops_list: operations list
  */
 struct genl_ops
@@ -64,6 +65,7 @@
 				       struct genl_info *info);
 	int		       (*dumpit)(struct sk_buff *skb,
 					 struct netlink_callback *cb);
+	int		       (*done)(struct netlink_callback *cb);
 	struct list_head	ops_list;
 };