ipv6: Kill rt6i_dev and rt6i_expires defines.

It just obscures that the netdevice pointer and the expires value are
implemented in the dst_entry sub-object of the ipv6 route.

And it makes grepping for dst_entry member uses much harder too.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index ea34d58..b853f06 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -162,7 +162,7 @@
 		struct rt6_info *rt;
 		rt = rt6_lookup(net, addr, NULL, 0, 0);
 		if (rt) {
-			dev = rt->rt6i_dev;
+			dev = rt->dst.dev;
 			dst_release(&rt->dst);
 		}
 	} else
@@ -256,7 +256,7 @@
 		struct rt6_info *rt = rt6_lookup(net, group, NULL, 0, 0);
 
 		if (rt) {
-			dev = rt->rt6i_dev;
+			dev = rt->dst.dev;
 			dev_hold(dev);
 			dst_release(&rt->dst);
 		}