iwlagn: declare static

Declare iwl_mac_rssi_callback as "static"

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index cbd8d10..3f2b9d6 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -3342,7 +3342,7 @@
 	kfree(priv->beacon_cmd);
 }
 
-void iwl_mac_rssi_callback(struct ieee80211_hw *hw,
+static void iwl_mac_rssi_callback(struct ieee80211_hw *hw,
 			   enum ieee80211_rssi_event rssi_event)
 {
 	struct iwl_priv *priv = hw->priv;