ath9k: disable periodic entropy gathering (keep initial) to fix some stability issues

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

SVN-Revision: 41952

package/kernel/mac80211/patches/550-ath9k_entropy_from_adc.patch

@@ -108,20 +108,6 @@
  #ifdef CPTCFG_ATH9K_BTCOEX_SUPPORT
  
  static inline void ath9k_hw_set_bt_ant_diversity(struct ath_hw *ah, bool enable)
---- a/drivers/net/wireless/ath/ath9k/link.c
-+++ b/drivers/net/wireless/ath/ath9k/link.c
-@@ -308,6 +308,11 @@ void ath_ani_calibrate(unsigned long dat
- 	unsigned int timestamp = jiffies_to_msecs(jiffies);
- 	u32 cal_interval, short_cal_interval, long_cal_interval;
- 	unsigned long flags;
-+	char buf[256];
-+
-+	/* gather entropy */
-+	ath9k_hw_get_adc_entropy(ah, buf, sizeof(buf));
-+	add_device_randomness(buf, sizeof(buf));
- 
- 	if (ah->caldata && test_bit(NFCAL_INTF, &ah->caldata->cal_flags))
- 		long_cal_interval = ATH_LONG_CALINTERVAL_INT;
 --- a/drivers/net/wireless/ath/ath9k/ar5008_phy.c
 +++ b/drivers/net/wireless/ath/ath9k/ar5008_phy.c
 @@ -1231,9 +1231,30 @@ static void ar5008_hw_set_radar_conf(str