ath9k: do not overwrite AR_PHY_RADAR_1 MSB

Do not overwrite AR_PHY_RADAR_1 most significant byte default value

Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi83@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/ar5008_phy.c b/drivers/net/wireless/ath/ath9k/ar5008_phy.c
index b72d0be..ba3d788 100644
--- a/drivers/net/wireless/ath/ath9k/ar5008_phy.c
+++ b/drivers/net/wireless/ath/ath9k/ar5008_phy.c
@@ -1190,7 +1190,7 @@
 static void ar5008_hw_set_radar_params(struct ath_hw *ah,
 				       struct ath_hw_radar_conf *conf)
 {
-	u32 radar_0 = 0, radar_1 = 0;
+	u32 radar_0 = 0, radar_1;
 
 	if (!conf) {
 		REG_CLR_BIT(ah, AR_PHY_RADAR_0, AR_PHY_RADAR_0_ENA);
@@ -1204,6 +1204,9 @@
 	radar_0 |= SM(conf->pulse_rssi, AR_PHY_RADAR_0_PRSSI);
 	radar_0 |= SM(conf->pulse_inband, AR_PHY_RADAR_0_INBAND);
 
+	radar_1 = REG_READ(ah, AR_PHY_RADAR_1);
+	radar_1 &= ~(AR_PHY_RADAR_1_MAXLEN | AR_PHY_RADAR_1_RELSTEP_THRESH |
+		     AR_PHY_RADAR_1_RELPWR_THRESH);
 	radar_1 |= AR_PHY_RADAR_1_MAX_RRSSI;
 	radar_1 |= AR_PHY_RADAR_1_BLOCK_CHECK;
 	radar_1 |= SM(conf->pulse_maxlen, AR_PHY_RADAR_1_MAXLEN);