net_sched: sch_fq: no longer use skb_is_tcp_pure_ack()

With the new EDT model, sch_fq no longer has to special
case TCP pure acks, since their skb->tstamp will allow them
being sent without pacing delay.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_fq.c

@@ -444,7 +444,7 @@ static struct sk_buff *fq_dequeue(struct Qdisc *sch)
 	}
 
 	skb = f->head;
-	if (skb && !skb_is_tcp_pure_ack(skb)) {
+	if (skb) {
 		u64 time_next_packet = max_t(u64, ktime_to_ns(skb->tstamp),
 					     f->time_next_packet);