ath9k_hw: Set default slottime as 9us

Initialize 9us slot time as that is what is used mostly
(for non-ERP cases) and also to be in sync with initvals.
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -440,7 +440,7 @@ static void ath9k_hw_init_defaults(struct ath_hw *ah)
 	if (AR_SREV_9100(ah))
 		ah->sta_id1_defaults |= AR_STA_ID1_AR9100_BA_FIX;
 	ah->enable_32kHz_clock = DONT_USE_32KHZ;
-	ah->slottime = 20;
+	ah->slottime = ATH9K_SLOT_TIME_9;
 	ah->globaltxtimeout = (u32) -1;
 	ah->power_mode = ATH9K_PM_UNDEFINED;
 }