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>
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index a18d975..13cc744 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -495,16 +495,15 @@
 
 void qdisc_watchdog_schedule(struct qdisc_watchdog *wd, psched_time_t expires)
 {
-	ktime_t time;
-
 	if (test_bit(__QDISC_STATE_DEACTIVATED,
 		     &qdisc_root_sleeping(wd->qdisc)->state))
 		return;
 
 	qdisc_throttled(wd->qdisc);
-	time = ktime_set(0, 0);
-	time = ktime_add_ns(time, PSCHED_TICKS2NS(expires));
-	hrtimer_start(&wd->timer, time, HRTIMER_MODE_ABS);
+
+	hrtimer_start(&wd->timer,
+		      ns_to_ktime(PSCHED_TICKS2NS(expires)),
+		      HRTIMER_MODE_ABS);
 }
 EXPORT_SYMBOL(qdisc_watchdog_schedule);