ath9k: Fix warning: symbol 'ath9k_platform_id_table' was not declared. Should it be static?

Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/ahb.c b/drivers/net/wireless/ath/ath9k/ahb.c
index 090f314..6195639 100644
--- a/drivers/net/wireless/ath/ath9k/ahb.c
+++ b/drivers/net/wireless/ath/ath9k/ahb.c
@@ -21,7 +21,7 @@
 #include <linux/ath9k_platform.h>
 #include "ath9k.h"
 
-const struct platform_device_id ath9k_platform_id_table[] = {
+static const struct platform_device_id ath9k_platform_id_table[] = {
 	{
 		.name = "ath9k",
 		.driver_data = AR5416_AR9100_DEVID,