net_sched: make qdisc_reset() smaller

For some unknown reason qdisc_reset() is using
a convoluted way of freeing two lists of skbs.

Use __skb_queue_purge() instead.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Link: https://lore.kernel.org/r/20220414011004.2378350-1-eric.dumazet@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

net/sched/sch_generic.c

@@ -1019,22 +1019,14 @@ EXPORT_SYMBOL(qdisc_create_dflt);
 void qdisc_reset(struct Qdisc *qdisc)
 {
 	const struct Qdisc_ops *ops = qdisc->ops;
-	struct sk_buff *skb, *tmp;
 
 	trace_qdisc_reset(qdisc);
 
 	if (ops->reset)
 		ops->reset(qdisc);
 
-	skb_queue_walk_safe(&qdisc->gso_skb, skb, tmp) {
-		__skb_unlink(skb, &qdisc->gso_skb);
-		kfree_skb_list(skb);
-	}
-
-	skb_queue_walk_safe(&qdisc->skb_bad_txq, skb, tmp) {
-		__skb_unlink(skb, &qdisc->skb_bad_txq);
-		kfree_skb_list(skb);
-	}
+	__skb_queue_purge(&qdisc->gso_skb);
+	__skb_queue_purge(&qdisc->skb_bad_txq);
 
 	qdisc->q.qlen = 0;
 	qdisc->qstats.backlog = 0;