bridge: is PACKET_LOOPBACK unlikely()?

While looking at using netdev_rx_handler_register for openvswitch Jesse
Gross suggested that an unlikely() might be worthwhile in that code.
I'm interested to see if its appropriate for the bridge code.

Cc: Jesse Gross <jesse@nicira.com>
Signed-off-by: NSimon Horman <horms@verge.net.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_input.c

@@ -141,7 +141,7 @@ struct sk_buff *br_handle_frame(struct sk_buff *skb)
 	const unsigned char *dest = eth_hdr(skb)->h_dest;
 	int (*rhook)(struct sk_buff *skb);
 
-	if (skb->pkt_type == PACKET_LOOPBACK)
+	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
 		return skb;
 
 	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))