iwlagn: move wait_for_tx_queue_empty to transport layer

This one is really transport related.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
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 724c50a..5d0888a 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2833,7 +2833,7 @@
 		}
 	}
 	IWL_DEBUG_MAC80211(priv, "wait transmit/flush all frames\n");
-	iwlagn_wait_tx_queue_empty(priv);
+	iwl_trans_wait_tx_queue_empty(trans(priv));
 done:
 	mutex_unlock(&priv->shrd->mutex);
 	IWL_DEBUG_MAC80211(priv, "leave\n");