mac80211: Don't call rate control when HW handles it

Rate control should not be called to update the tx status
when HW does the RC.

Signed-off-by: Vasanthakumar <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/rate.h

@@ -44,6 +44,10 @@ static inline void rate_control_tx_status(struct ieee80211_local *local,
 	struct rate_control_ref *ref = local->rate_ctrl;
 	struct ieee80211_sta *ista = &sta->sta;
 	void *priv_sta = sta->rate_ctrl_priv;
+
+	if (!ref)
+		return;
+
 	ref->ops->tx_status(ref->priv, sband, ista, priv_sta, skb);
 }