cfg80211: clean up beacon loss CQM event

Having it as a sub-event for RSSI thresholds is very ugly,
but luckily no userspace actually uses the events yet.

Move the event to its own function call internally and to
its own event attribute in nl80211.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index cff3a26..66cbfe4 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -4672,6 +4672,14 @@
 			       gfp_t gfp);
 
 /**
+ * ieee80211_cqm_beacon_loss_notify - inform CQM of beacon loss
+ *
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback.
+ * @gfp: context flags
+ */
+void ieee80211_cqm_beacon_loss_notify(struct ieee80211_vif *vif, gfp_t gfp);
+
+/**
  * ieee80211_radar_detected - inform that a radar was detected
  *
  * @hw: pointer as obtained from ieee80211_alloc_hw()