mac80211: add beacon filtering support

Add IEEE80211_HW_BEACON_FILTERING flag so that driver inform that it supports
beacon filtering. Drivers need to call the new function
ieee80211_beacon_loss() to notify about beacon loss.

Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 8a617a7..acba78e 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -275,6 +275,7 @@
 	struct timer_list chswitch_timer;
 	struct work_struct work;
 	struct work_struct chswitch_work;
+	struct work_struct beacon_loss_work;
 
 	u8 bssid[ETH_ALEN], prev_bssid[ETH_ALEN];
 
@@ -1086,6 +1087,7 @@
 			     int powersave);
 void ieee80211_sta_rx_notify(struct ieee80211_sub_if_data *sdata,
 			     struct ieee80211_hdr *hdr);
+void ieee80211_beacon_loss_work(struct work_struct *work);
 
 void ieee80211_wake_queues_by_reason(struct ieee80211_hw *hw,
 				     enum queue_stop_reason reason);