Revert "net: release skb->dst in sock_queue_rcv_skb()"

This reverts commit 70355602879229c6f8bd694ec9c0814222bc4936.

As pointed out by Mark McLoughlin IP_PKTINFO cmsg data is one
post-queueing user, so this optimization is not valid right
now.

Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/sock.c

@@ -289,11 +289,7 @@ int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 
 	skb->dev = NULL;
 	skb_set_owner_r(skb, sk);
-	/*
-	 * release dst right now while its hot
-	 */
-	dst_release(skb->dst);
-	skb->dst = NULL;
+
 	/* Cache the SKB length before we tack it onto the receive
 	 * queue.  Once it is added it no longer belongs to us and
 	 * may be freed by other threads of control pulling packets