cfg80211: process pending events when unregistering net device

libertas currently calls cfg80211_disconnected() when it is being
brought down. This causes an event to be allocated, but since the
wdev is already removed from the rdev by the time that the event
processing work executes, the event is never processed or freed.
http://article.gmane.org/gmane.linux.kernel.wireless.general/95666

Fix this leak, and other possible situations, by processing the event
queue when a device is being unregistered. Thanks to Johannes Berg for
the suggestion.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Cc: stable@vger.kernel.org
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 31b40cc..dcd64d5 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -952,6 +952,11 @@
 		 */
 		synchronize_rcu();
 		INIT_LIST_HEAD(&wdev->list);
+		/*
+		 * Ensure that all events have been processed and
+		 * freed.
+		 */
+		cfg80211_process_wdev_events(wdev);
 		break;
 	case NETDEV_PRE_UP:
 		if (!(wdev->wiphy->interface_modes & BIT(wdev->iftype)))