ipv6: Store route neighbour in rt6_info struct.

This makes for a simplified conversion away from dst_get_neighbour*().

All code outside of ipv6 will use neigh lookups via dst_neigh_lookup*().

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index a192f78..0fedbd8 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -86,6 +86,8 @@
 struct rt6_info {
 	struct dst_entry		dst;
 
+	struct neighbour		*n;
+
 	/*
 	 * Tail elements of dst_entry (__refcnt etc.)
 	 * and these elements (rarely used in hot path) are in