net_sched: Add qdisc __NET_XMIT_BYPASS flag

Patrick McHardy <kaber@trash.net> noticed that it would be nice to
handle NET_XMIT_BYPASS by NET_XMIT_SUCCESS with an internal qdisc flag
__NET_XMIT_BYPASS and to remove the mapping from dev_queue_xmit().

David Miller <davem@davemloft.net> spotted a serious bug in the first
version of this patch.

Signed-off-by: Jarek Poplawski <jarkao2@gmail.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 27dd773..43d3725 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -457,7 +457,7 @@
 		return 0;
 	}
 	tasklet_schedule(&p->task);
-	return NET_XMIT_BYPASS;
+	return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 }
 
 /*