pkt_sched: Add qdisc_all_tx_empty()

This is a helper function, currently used by IRDA.

This is being added so that we can contain and isolate as many
explicit ->tx_queue references in the tree as possible.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/irda/irda_device.h b/include/net/irda/irda_device.h
index 16fbf67..3025ae1 100644
--- a/include/net/irda/irda_device.h
+++ b/include/net/irda/irda_device.h
@@ -223,7 +223,7 @@
 /* Interface for internal use */
 static inline int irda_device_txqueue_empty(const struct net_device *dev)
 {
-	return skb_queue_empty(&dev->tx_queue.qdisc->q);
+	return qdisc_all_tx_empty(dev);
 }
 int  irda_device_set_raw_mode(struct net_device* self, int status);
 struct net_device *alloc_irdadev(int sizeof_priv);