mac80211: fix dialog token allocator

The dialog token allocator has apparently been broken
since b83f4e15 ("mac80211: fix deadlock in sta->lock")
because it got moved out under the spinlock. Fix it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/agg-tx.c

@@ -332,14 +332,16 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
 		IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
 
 	spin_unlock(&local->ampdu_lock);
-	spin_unlock_bh(&sta->lock);
 
-	/* send an addBA request */
+	/* prepare tid data */
 	sta->ampdu_mlme.dialog_token_allocator++;
 	sta->ampdu_mlme.tid_tx[tid]->dialog_token =
 			sta->ampdu_mlme.dialog_token_allocator;
 	sta->ampdu_mlme.tid_tx[tid]->ssn = start_seq_num;
 
+	spin_unlock_bh(&sta->lock);
+
+	/* send AddBA request */
 	ieee80211_send_addba_request(sdata, pubsta->addr, tid,
 			 sta->ampdu_mlme.tid_tx[tid]->dialog_token,
 			 sta->ampdu_mlme.tid_tx[tid]->ssn,