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>

net/mac80211/trace.h

@@ -1829,6 +1829,12 @@ TRACE_EVENT(api_cqm_rssi_notify,
 	)
 );
 
+DEFINE_EVENT(local_sdata_evt, api_cqm_beacon_loss_notify,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata),
+	TP_ARGS(local, sdata)
+);
+
 TRACE_EVENT(api_scan_completed,
 	TP_PROTO(struct ieee80211_local *local, bool aborted),