pkt_sched: Fix warning false positives.

GCC refuses to recognize that all error control flows do in fact
set err to something.

Add an explicit initialization to shut it up.

net/sched/sch_drr.c: In function ‘drr_enqueue’:
net/sched/sch_drr.c:359:11: warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized]
net/sched/sch_qfq.c: In function ‘qfq_enqueue’:
net/sched/sch_qfq.c:885:11: warning: ‘err’ may be used uninitialized in this function [-Wmaybe-uninitialized]
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_drr.c

@@ -352,7 +352,7 @@ static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 {
 	struct drr_sched *q = qdisc_priv(sch);
 	struct drr_class *cl;
-	int err;
+	int err = 0;
 
 	cl = drr_classify(skb, sch, &err);
 	if (cl == NULL) {

net/sched/sch_qfq.c

@@ -878,7 +878,7 @@ static int qfq_enqueue(struct sk_buff *skb, struct Qdisc *sch)
 {
 	struct qfq_sched *q = qdisc_priv(sch);
 	struct qfq_class *cl;
-	int err;
+	int err = 0;
 
 	cl = qfq_classify(skb, sch, &err);
 	if (cl == NULL) {