ath9k_hw: add support for GPIO differences on AR9003

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/reg.h b/drivers/net/wireless/ath/ath9k/reg.h
index d56b4ea..d524891 100644
--- a/drivers/net/wireless/ath/ath9k/reg.h
+++ b/drivers/net/wireless/ath/ath9k/reg.h
@@ -954,6 +954,7 @@
 #define AR9285_NUM_GPIO                          12
 #define AR9287_NUM_GPIO                          11
 #define AR9271_NUM_GPIO                          16
+#define AR9300_NUM_GPIO                          17
 
 #define AR_GPIO_IN_OUT                           0x4048
 #define AR_GPIO_IN_VAL                           0x0FFFC000