net: sched: fix misuse of qcpu->backlog in gnet_stats_add_queue_cpu

In the gnet_stats_add_queue_cpu function, the qstats->qlen statistics
are incorrectly set to qcpu->backlog.

Fixes: 448e163f ("gen_stats: Add gnet_stats_add_queue()")
Signed-off-by: NZhengchao Shao <shaozhengchao@huawei.com>
Link: https://lore.kernel.org/r/20220815030848.276746-1-shaozhengchao@huawei.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

net/core/gen_stats.c

@@ -345,7 +345,7 @@ static void gnet_stats_add_queue_cpu(struct gnet_stats_queue *qstats,
 	for_each_possible_cpu(i) {
 		const struct gnet_stats_queue *qcpu = per_cpu_ptr(q, i);
 
-		qstats->qlen += qcpu->backlog;
+		qstats->qlen += qcpu->qlen;
 		qstats->backlog += qcpu->backlog;
 		qstats->drops += qcpu->drops;
 		qstats->requeues += qcpu->requeues;