net-next: remove useless union keyword

remove useless union keyword in rtable, rt6_info and dn_route.

Since there is only one member in a union, the union keyword isn't useful.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c
index 62ec021..1841388 100644
--- a/net/netfilter/xt_TCPMSS.c
+++ b/net/netfilter/xt_TCPMSS.c
@@ -165,8 +165,8 @@
 	rcu_read_unlock();
 
 	if (rt != NULL) {
-		mtu = dst_mtu(&rt->u.dst);
-		dst_release(&rt->u.dst);
+		mtu = dst_mtu(&rt->dst);
+		dst_release(&rt->dst);
 	}
 	return mtu;
 }