rt2x00: Add kill_tx_queue callback function

provide rt2x00lib the possibility to kill a particular TX queue.
This can be useful when disabling the radio, but more importantly
will allow beaconing to be disabled when mac80211 requests this
(during scanning for example)

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2x00usb.h b/drivers/net/wireless/rt2x00/rt2x00usb.h
index fe45238..bd2d59c 100644
--- a/drivers/net/wireless/rt2x00/rt2x00usb.h
+++ b/drivers/net/wireless/rt2x00/rt2x00usb.h
@@ -419,6 +419,17 @@
 void rt2x00usb_kick_tx_queue(struct rt2x00_dev *rt2x00dev,
 			     const enum data_queue_qid qid);
 
+/**
+ * rt2x00usb_kill_tx_queue - Kill data queue
+ * @rt2x00dev: Pointer to &struct rt2x00_dev
+ * @qid: Data queue to kill
+ *
+ * This will walk through all entries of the queue and kill all
+ * previously kicked frames before they can be send.
+ */
+void rt2x00usb_kill_tx_queue(struct rt2x00_dev *rt2x00dev,
+			      const enum data_queue_qid qid);
+
 /*
  * Device initialization handlers.
  */