iwlagn: add debug for mac80211 callback

Add IWL_DEBUG_MAC80211 debug for all mac80211 callback function

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-rxon.c b/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
index ca632f9..8155522 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rxon.c
@@ -539,7 +539,7 @@
 	const struct iwl_channel_info *ch_info;
 	int ret = 0;
 
-	IWL_DEBUG_MAC80211(priv, "changed %#x", changed);
+	IWL_DEBUG_MAC80211(priv, "enter: changed %#x", changed);
 
 	mutex_lock(&priv->shrd->mutex);
 
@@ -657,6 +657,8 @@
 	}
  out:
 	mutex_unlock(&priv->shrd->mutex);
+	IWL_DEBUG_MAC80211(priv, "leave\n");
+
 	return ret;
 }