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_tbf.c b/net/sched/sch_tbf.c
index 0991c64..641a30d 100644
--- a/net/sched/sch_tbf.c
+++ b/net/sched/sch_tbf.c
@@ -127,7 +127,7 @@
 		return qdisc_reshape_fail(skb, sch);
 
 	ret = qdisc_enqueue(skb, q->qdisc);
-	if (ret != 0) {
+	if (ret != NET_XMIT_SUCCESS) {
 		if (net_xmit_drop_count(ret))
 			sch->qstats.drops++;
 		return ret;
@@ -136,7 +136,7 @@
 	sch->q.qlen++;
 	sch->bstats.bytes += qdisc_pkt_len(skb);
 	sch->bstats.packets++;
-	return 0;
+	return NET_XMIT_SUCCESS;
 }
 
 static unsigned int tbf_drop(struct Qdisc* sch)