ath9k: fix a chip wakeup related crash in ath9k_start

commit f62d816f upstream.

When the chip is still asleep when ath9k_start is called,
ath9k_hw_configpcipowersave can trigger a data bus error.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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

@@ -1918,6 +1918,8 @@ static int ath9k_start(struct ieee80211_hw *hw)
 	DPRINTF(sc, ATH_DBG_CONFIG, "Starting driver with "
 		"initial channel: %d MHz\n", curchan->center_freq);
 
+	ath9k_ps_wakeup(sc);
+
 	mutex_lock(&sc->mutex);
 
 	if (ath9k_wiphy_started(sc)) {
@@ -2025,6 +2027,8 @@ static int ath9k_start(struct ieee80211_hw *hw)
 mutex_unlock:
 	mutex_unlock(&sc->mutex);
 
+	ath9k_ps_restore(sc);
+
 	return r;
 }