cfg80211: Add nl80211 event for deletion of a station entry

Indicate an NL80211_CMD_DEL_STATION event when a station entry in
mac80211 is deleted to match with the NL80211_CMD_NEW_STATION event
that is used when the entry was added. This is needed, e.g., to allow
user space to remove a peer from RSN IBSS Authenticator state machine
to avoid re-authentication and re-keying delays when the peer is not
reachable anymore.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/wireless/mlme.c b/net/wireless/mlme.c
index aa5df88..16881fe 100644
--- a/net/wireless/mlme.c
+++ b/net/wireless/mlme.c
@@ -770,6 +770,15 @@
 }
 EXPORT_SYMBOL(cfg80211_new_sta);
 
+void cfg80211_del_sta(struct net_device *dev, const u8 *mac_addr, gfp_t gfp)
+{
+	struct wiphy *wiphy = dev->ieee80211_ptr->wiphy;
+	struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
+
+	nl80211_send_sta_del_event(rdev, dev, mac_addr, gfp);
+}
+EXPORT_SYMBOL(cfg80211_del_sta);
+
 struct cfg80211_mgmt_registration {
 	struct list_head list;