[IPV4]: Remove likely in ip_rcv_finish()

This is another result from my likely profiling tool
(dwalker@mvista.com just sent the patch of the profiling tool to
linux-kernel mailing list, which is similar to what I use).

On my system (not very busy, normal development machine within a
VMWare workstation), I see a 6/5 miss/hit ratio for this "likely".
Signed-off-by: NHua Zhong <hzhong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/ip_input.c

@@ -337,7 +337,7 @@ static inline int ip_rcv_finish(struct sk_buff *skb)
 	 *	Initialise the virtual path cache for the packet. It describes
 	 *	how the packet travels inside Linux networking.
 	 */ 
-	if (likely(skb->dst == NULL)) {
+	if (skb->dst == NULL) {
 		int err = ip_route_input(skb, iph->daddr, iph->saddr, iph->tos,
 					 skb->dev);
 		if (unlikely(err)) {