ath9k_htc: set IEEE80211_TX_STAT_AMPDU for acked aggregated frames

Frame aggregation requires the IEEE80211_TX_STAT_AMPDU to
be set so that mac80211 can report the last_tx_rate correctly.
Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/htc_drv_txrx.c

@@ -471,8 +471,11 @@ static void ath9k_htc_tx_process(struct ath9k_htc_priv *priv,
 	if (!txok || !vif || !txs)
 		goto send_mac80211;
 
-	if (txs->ts_flags & ATH9K_HTC_TXSTAT_ACK)
+	if (txs->ts_flags & ATH9K_HTC_TXSTAT_ACK) {
 		tx_info->flags |= IEEE80211_TX_STAT_ACK;
+		if (tx_info->flags & IEEE80211_TX_CTL_AMPDU)
+			tx_info->flags |= IEEE80211_TX_STAT_AMPDU;
+	}
 
 	if (txs->ts_flags & ATH9K_HTC_TXSTAT_FILT)
 		tx_info->flags |= IEEE80211_TX_STAT_TX_FILTERED;