ath9k_hw: fix MAC clock for half/quarter rate

Enabling half/quarter rate makes the MAC run at half/quarter clock speed.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -99,6 +99,13 @@ static void ath9k_hw_set_clockrate(struct ath_hw *ah)
 	if (conf_is_ht40(conf))
 		clockrate *= 2;
 
+	if (ah->curchan) {
+		if (IS_CHAN_HALF_RATE(ah->curchan))
+			clockrate /= 2;
+		if (IS_CHAN_QUARTER_RATE(ah->curchan))
+			clockrate /= 4;
+	}
+
 	common->clockrate = clockrate;
 }