ath9k: Fix wifi disconnection when collocated bt scan is active

As all bt packets are priority traffic during bt scan, wifi
will get disconnected when bt scan lasts for few seconds. Fix
this by allocating 10% of bt period time (4.5ms) to wifi fully.

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/btcoex.h

@@ -25,10 +25,12 @@
 
 #define ATH_BTCOEX_DEF_BT_PERIOD  45
 #define ATH_BTCOEX_DEF_DUTY_CYCLE 55
+#define ATH_BTCOEX_BTSCAN_DUTY_CYCLE 90
 #define ATH_BTCOEX_BMISS_THRESH   50
 
 #define ATH_BT_PRIORITY_TIME_THRESHOLD 1000 /* ms */
 #define ATH_BT_CNT_THRESHOLD	       3
+#define ATH_BT_CNT_SCAN_THRESHOLD      15
 
 enum ath_btcoex_scheme {
 	ATH_BTCOEX_CFG_NONE,