ath9k: remove driver ASSERT, just use BUG_ON()

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/hw.c b/drivers/net/wireless/ath/ath9k/hw.c
index 9d03d27..93da19c 100644
--- a/drivers/net/wireless/ath/ath9k/hw.c
+++ b/drivers/net/wireless/ath/ath9k/hw.c
@@ -3814,7 +3814,7 @@
 {
 	u32 gpio_shift;
 
-	ASSERT(gpio < ah->caps.num_gpio_pins);
+	BUG_ON(gpio >= ah->caps.num_gpio_pins);
 
 	gpio_shift = gpio << 1;