ath9k_hw: add support for 8 AP mode interfaces

Also tweak beacon response times for better stability with the shorter
timer intervals.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 0a37631..a277cf6 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -370,7 +370,7 @@
  * number of beacon intervals, the game's up.
  */
 #define BSTUCK_THRESH           	9
-#define	ATH_BCBUF               	4
+#define	ATH_BCBUF               	8
 #define ATH_DEFAULT_BINTVAL     	100 /* TU */
 #define ATH_DEFAULT_BMISS_LIMIT 	10
 #define IEEE80211_MS_TO_TU(x)           (((x) * 1000) / 1024)