[ICSK]: Generalise tcp_listen_{start,stop}

This also moved inet_iif from tcp to inet_hashtables.h, as it is
needed by the inet_lookup callers, perhaps this needs a bit of
polishing, but for now seems fine.

Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 7137e64..f691058 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -202,7 +202,7 @@
 	 * we can only allow the backlog to be adjusted.
 	 */
 	if (old_state != TCP_LISTEN) {
-		err = tcp_listen_start(sk);
+		err = inet_csk_listen_start(sk, TCP_SYNQ_HSIZE);
 		if (err)
 			goto out;
 	}