pkt_sched: use ns_to_ktime() helper

ns_to_ktime() seems better than ktime_set() + ktime_add_ns()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_cbq.c

@@ -509,8 +509,7 @@ static void cbq_ovl_delay(struct cbq_class *cl)
 			cl->cpriority = TC_CBQ_MAXPRIO;
 			q->pmask |= (1<<TC_CBQ_MAXPRIO);
 
-			expires = ktime_set(0, 0);
-			expires = ktime_add_ns(expires, PSCHED_TICKS2NS(sched));
+			expires = ns_to_ktime(PSCHED_TICKS2NS(sched));
 			if (hrtimer_try_to_cancel(&q->delay_timer) &&
 			    ktime_to_ns(ktime_sub(
 					hrtimer_get_expires(&q->delay_timer),