iwlwifi: make "Tx aggregation enabled on ra =" be at DEBUG level

Average users either don't care or they think that message indicates a
problem...

Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index c664c27..339e8d9 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -620,7 +620,7 @@
 	sta_priv->lq_sta.lq.agg_params.agg_frame_cnt_limit =
 		sta_priv->max_agg_bufsize;
 
-	IWL_INFO(priv, "Tx aggregation enabled on ra = %pM tid = %d\n",
+	IWL_DEBUG_HT(priv, "Tx aggregation enabled on ra = %pM tid = %d\n",
 		 sta->addr, tid);
 
 	return iwl_send_lq_cmd(priv, ctx,