ath9k: always issue a full hw reset after waking up from full-sleep mode

After waking up from full sleep, registers are accessible, but rx/tx
typically fails. A fast channel change will not recover from this, so
ensure that a full-sleep -> wake transition is always followed by a full
reset.

The reason why this hasn't created any serious problems yet is that it's
hidden by the (wrong) behavior of enabling/disabling the radio when the
wiphy idle state changes.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -1954,7 +1954,7 @@ static void ath_tx_complete(struct ath_softc *sc, struct sk_buff *skb,
 		skb_pull(skb, padsize);
 	}
 
-	if (sc->ps_flags & PS_WAIT_FOR_TX_ACK) {
+	if ((sc->ps_flags & PS_WAIT_FOR_TX_ACK) && !txq->axq_depth) {
 		sc->ps_flags &= ~PS_WAIT_FOR_TX_ACK;
 		ath_dbg(common, ATH_DBG_PS,
 			"Going back to sleep after having received TX status (0x%lx)\n",