iwlwifi: send tx_power_cmd synchronously

On 5xxx and 6xxx change to send tx_power_cmd command synchronously,
to do not start other commands when setting tx power is pending.
We currently do the same for 4956 and 3945.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by:  Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-agn-lib.c

@@ -526,9 +526,8 @@ int iwlagn_send_tx_power(struct iwl_priv *priv)
 	else
 		tx_ant_cfg_cmd = REPLY_TX_POWER_DBM_CMD;
 
-	return  iwl_send_cmd_pdu_async(priv, tx_ant_cfg_cmd,
-				       sizeof(tx_power_cmd), &tx_power_cmd,
-				       NULL);
+	return iwl_send_cmd_pdu(priv, tx_ant_cfg_cmd, sizeof(tx_power_cmd),
+				&tx_power_cmd);
 }
 
 void iwlagn_temperature(struct iwl_priv *priv)