net: Abstract dst->neighbour accesses behind helpers.

dst_{get,set}_neighbour()

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 8871067..d7bb94c 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -731,9 +731,9 @@
 		}
 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 		else if (skb->protocol == htons(ETH_P_IPV6)) {
+			struct neighbour *neigh = dst_get_neighbour(skb_dst(skb));
 			const struct in6_addr *addr6;
 			int addr_type;
-			struct neighbour *neigh = skb_dst(skb)->neighbour;
 
 			if (neigh == NULL)
 				goto tx_error;