inet: ip early demux should avoid request sockets

When a request socket is created, we do not cache ip route
dst entry, like for timewait sockets.

Let's use sk_fullsock() helper.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index d89f028..e4761b2 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1583,7 +1583,7 @@
 	if (sk) {
 		skb->sk = sk;
 		skb->destructor = sock_edemux;
-		if (sk->sk_state != TCP_TIME_WAIT) {
+		if (sk_fullsock(sk)) {
 			struct dst_entry *dst = sk->sk_rx_dst;
 
 			if (dst)