[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/net/netlink/genetlink.c b/net/netlink/genetlink.c
index cc874f0..b9b0374 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -331,7 +331,7 @@
 		}
 
 		*errp = err = netlink_dump_start(genl_sock, skb, nlh,
-						 ops->dumpit, NULL);
+						 ops->dumpit, ops->done);
 		if (err == 0)
 			skb_pull(skb, min(NLMSG_ALIGN(nlh->nlmsg_len),
 					  skb->len));