iwlagn: add documentation to the transport layer

and do a few clean up fixes on the way

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-trans.c b/drivers/net/wireless/iwlwifi/iwl-trans.c
index 209dd7e..d4f6281 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans.c
@@ -1300,6 +1300,8 @@
 						    sta_id, tid);
 		}
 		break;
+	default:
+		break;
 	}
 
 	return 0;
@@ -1326,10 +1328,10 @@
 {
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 	struct iwl_tx_queue *txq = &trans_pcie->txq[txq_id];
+	enum iwl_agg_state agg_state;
 	/* n_bd is usually 256 => n_bd - 1 = 0xff */
 	int tfd_num = ssn & (txq->q.n_bd - 1);
 	int freed = 0;
-	u8 agg_state;
 	bool cond;
 
 	txq->time_stamp = jiffies;