iwlwifi: fix ack health for WiFi/BT combo devices

Combo devices have TX statistics on different place, because
struct statistics_rx_bt and struct statistics_rx have different
size. User proper values on combo devices instead of random data.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn.c

@@ -1419,8 +1419,13 @@ bool iwl_good_ack_health(struct iwl_priv *priv, struct iwl_rx_packet *pkt)
 	if (priv->_agn.agg_tids_count)
 		return true;
 
-	cur = &pkt->u.stats.tx;
-	old = &priv->_agn.statistics.tx;
+	if (iwl_bt_statistics(priv)) {
+		cur = &pkt->u.stats_bt.tx;
+		old = &priv->_agn.statistics_bt.tx;
+	} else {
+		cur = &pkt->u.stats.tx;
+		old = &priv->_agn.statistics.tx;
+	}
 
 	actual_delta = le32_to_cpu(cur->actual_ack_cnt) -
 		       le32_to_cpu(old->actual_ack_cnt);