net_sched: sch_netem: defer skb freeing

rtnl_kfree_skbs() can be used in tfifo_reset()

It would be nice if we could iterate through rb tree instead
of removing one skb at a time, and build a single skb chain.
But this is left for a future patch.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/sch_netem.c

@@ -368,9 +368,7 @@ static void tfifo_reset(struct Qdisc *sch)
 		struct sk_buff *skb = netem_rb_to_skb(p);
 
 		rb_erase(p, &q->t_root);
-		skb->next = NULL;
-		skb->prev = NULL;
-		kfree_skb(skb);
+		rtnl_kfree_skbs(skb, skb);
 	}
 }