pkt_sched: Fix qstats.qlen updating in dump_stats

Some classful qdiscs miss qstats.qlen updating with q.qlen of their
child qdiscs in dump_stats methods.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index 0f73c41..93285ce 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -322,6 +322,7 @@
 	struct Qdisc *cl_q;
 
 	cl_q = q->queues[cl - 1];
+	cl_q->qstats.qlen = cl_q->q.qlen;
 	if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 ||
 	    gnet_stats_copy_queue(d, &cl_q->qstats) < 0)
 		return -1;