sch_cbq: remove unnecessary null pointer check

It already has a NULL pointer check of rtab in qdisc_put_rtab().
Remove the check outside of qdisc_put_rtab().

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index d5a8a4b..e251833 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -1783,8 +1783,7 @@
 						    qdisc_root_sleeping_lock(sch),
 						    tca[TCA_RATE]);
 			if (err) {
-				if (rtab)
-					qdisc_put_rtab(rtab);
+				qdisc_put_rtab(rtab);
 				return err;
 			}
 		}