ath9k_hw: fix hardware queue allocation

commit ad8fdccf upstream.

The driver passes the desired hardware queue index for a WMM data queue
in qinfo->tqi_subtype. This was ignored in ath9k_hw_setuptxqueue, which
instead relied on the order in which the function is called.
Reported-by: Hubert Feurstein <h.feurstein@gmail.com>
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

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

@@ -311,14 +311,7 @@ int ath9k_hw_setuptxqueue(struct ath_hw *ah, enum ath9k_tx_queue type,
 		q = ATH9K_NUM_TX_QUEUES - 3;
 		break;
 	case ATH9K_TX_QUEUE_DATA:
-		for (q = 0; q < ATH9K_NUM_TX_QUEUES; q++)
-			if (ah->txq[q].tqi_type ==
-			    ATH9K_TX_QUEUE_INACTIVE)
-				break;
-		if (q == ATH9K_NUM_TX_QUEUES) {
-			ath_err(common, "No available TX queue\n");
-			return -1;
-		}
+		q = qinfo->tqi_subtype;
 		break;
 	default:
 		ath_err(common, "Invalid TX queue type: %u\n", type);