rt2x00: Move TX/RX work into dedicated workqueue

The TX/RX work structures must be able to run independently
of other workqueues. This is because mac80211 might use
the flush() callback function from various context, which depends
on the TX/RX work to complete while the main thread is blocked
(until the the TX queues are empty).

This should reduce the number of  'Queue %d failed to flush' warnings.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index 7661e4f..39bc2fa 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -860,6 +860,13 @@
 	 */
 	struct ieee80211_low_level_stats low_level_stats;
 
+	/**
+	 * Work queue for all work which should not be placed
+	 * on the mac80211 workqueue (because of dependencies
+	 * between various work structures).
+	 */
+	struct workqueue_struct *workqueue;
+
 	/*
 	 * Scheduled work.
 	 * NOTE: intf_work will use ieee80211_iterate_active_interfaces()