mac80211: set wifi_acked[_valid] bits for transmitted SKBs

There may be situations in which the in-kernel originator of an
SKB cares about its wifi transmission status. To have that, set
the wifi_acked[_valid] bits before freeing/orphaning the SKB if
the destructor is set. The originator can then use it in there.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/status.c

@@ -541,6 +541,11 @@ static void ieee80211_report_used_skb(struct ieee80211_local *local,
 	} else if (info->ack_frame_id) {
 		ieee80211_report_ack_skb(local, info, acked, dropped);
 	}
+
+	if (!dropped && skb->destructor) {
+		skb->wifi_acked_valid = 1;
+		skb->wifi_acked = acked;
+	}
 }
 
 /*