ath9k_hw: check for asynchronous interrupts before bailing out

in ar9003_hw_get_isr we bail out if we don't have any primary
interrupts and synchronous interrupts, also make sure we don't
have any asynchronous interrupts

Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/ar9003_mac.c

@@ -220,7 +220,7 @@ static bool ar9003_hw_get_isr(struct ath_hw *ah, enum ath9k_int *masked)
 
 	*masked = 0;
 
-	if (!isr && !sync_cause)
+	if (!isr && !sync_cause && !async_cause)
 		return false;
 
 	if (isr) {