net: Use NET_XMIT_SUCCESS where possible.

This is based on work originally done by Patric McHardy.

Signed-off-by: Ben Greear <greearb@candelatech.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 d8e0ae5..b8bcb20 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -334,7 +334,7 @@
 	if (++sch->q.qlen <= q->limit) {
 		sch->bstats.bytes += qdisc_pkt_len(skb);
 		sch->bstats.packets++;
-		return 0;
+		return NET_XMIT_SUCCESS;
 	}
 
 	sfq_drop(sch);