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_atm.c b/net/sched/sch_atm.c
index e114f23..34066278 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -418,7 +418,7 @@
 	}
 
 	ret = qdisc_enqueue(skb, flow->q);
-	if (ret != 0) {
+	if (ret != NET_XMIT_SUCCESS) {
 drop: __maybe_unused
 		if (net_xmit_drop_count(ret)) {
 			sch->qstats.drops++;
@@ -442,7 +442,7 @@
 	 */
 	if (flow == &p->link) {
 		sch->q.qlen++;
-		return 0;
+		return NET_XMIT_SUCCESS;
 	}
 	tasklet_schedule(&p->task);
 	return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;