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_output.c b/net/ipv4/ip_output.c
index db296a9..be27e60 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -204,7 +204,7 @@
 		skb = skb2;
 	}
 
-	neigh = dst->neighbour;
+	neigh = dst_get_neighbour(dst);
 	if (neigh)
 		return neigh_output(neigh, skb);