pkt_sched: Annotate uninitialized var in sfq_enqueue()

Some gcc versions warn that ret may be used uninitialized in
sfq_enqueue(). It's a false positive, so let's annotate this.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index ab8cfee..f3965df 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -281,7 +281,7 @@
 	struct sfq_sched_data *q = qdisc_priv(sch);
 	unsigned int hash;
 	sfq_index x;
-	int ret;
+	int uninitialized_var(ret);
 
 	hash = sfq_classify(skb, sch, &ret);
 	if (hash == 0) {