net_sched: remove some unnecessary checks in classful schedulers

The class argument to the ->graft(), ->leaf(), ->dump(), ->dump_stats() all
originate from either ->get() or ->walk() and are always valid.

Remove unnecessary checks.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index dad0144..375d64c 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1203,8 +1203,6 @@
 {
 	struct hfsc_class *cl = (struct hfsc_class *)arg;
 
-	if (cl == NULL)
-		return -ENOENT;
 	if (cl->level > 0)
 		return -EINVAL;
 	if (new == NULL) {
@@ -1228,7 +1226,7 @@
 {
 	struct hfsc_class *cl = (struct hfsc_class *)arg;
 
-	if (cl != NULL && cl->level == 0)
+	if (cl->level == 0)
 		return cl->qdisc;
 
 	return NULL;