ath9k: stop rx dma before stopping tx

It has been found that active Rx can interfere with stopping tx DMA, which
could result in at least parts of those "Failed to stop Tx DMA!" messages.
Stopping rx before tx should prevent that.
Signed-off-by: NFelix Fietkau <nbd@openwrt.org>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

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

@@ -239,7 +239,7 @@ static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx, bool flush)
 {
 	struct ath_hw *ah = sc->sc_ah;
 	struct ath_common *common = ath9k_hw_common(ah);
-	bool ret;
+	bool ret = true;
 
 	ieee80211_stop_queues(sc->hw);
 
@@ -250,11 +250,12 @@ static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx, bool flush)
 	ath9k_debug_samp_bb_mac(sc);
 	ath9k_hw_disable_interrupts(ah);
 
-	ret = ath_drain_all_txq(sc, retry_tx);
-
 	if (!ath_stoprecv(sc))
 		ret = false;
 
+	if (!ath_drain_all_txq(sc, retry_tx))
+		ret = false;
+
 	if (!flush) {
 		if (ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
 			ath_rx_tasklet(sc, 1, true);