carl9170: fix timekeeping for HW_COUNTER firmwares

AR9170_PWR_REG_PLL_ADDAC is used to set the main clock
divisor which affects the AHB/CPU speed. Because this
would interfere with the firmware internal timekeeping,
the function has to be moved into the firmware.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/carl9170/phy.c b/drivers/net/wireless/ath/carl9170/phy.c
index aa147a9..8635c5c 100644
--- a/drivers/net/wireless/ath/carl9170/phy.c
+++ b/drivers/net/wireless/ath/carl9170/phy.c
@@ -578,11 +578,10 @@
 	if (err)
 		return err;
 
-	/* XXX: remove magic! */
-	if (is_2ghz)
-		err = carl9170_write_reg(ar, AR9170_PWR_REG_PLL_ADDAC, 0x5163);
-	else
-		err = carl9170_write_reg(ar, AR9170_PWR_REG_PLL_ADDAC, 0x5143);
+	if (!ar->fw.hw_counters) {
+		err = carl9170_write_reg(ar, AR9170_PWR_REG_PLL_ADDAC,
+					 is_2ghz ? 0x5163 : 0x5143);
+	}
 
 	return err;
 }