mavlink: new args to request message, omit param1

We can omit param1 because it is already used for the message_id, so
it's basically duplicate information and won't get used anywhere.

src/modules/mavlink/mavlink_stream.h

@@ -96,7 +96,7 @@ public:
 	 * This function is called in response to a MAV_CMD_REQUEST_MESSAGE command. The default implementation is to
 	 * just reset the counter to immediately send one message.
 	 */
-	virtual bool request_message(float param1 = 0.0, float param2 = 0.0, float param3 = 0.0, float param4 = 0.0,
+	virtual bool request_message(float param2 = 0.0, float param3 = 0.0, float param4 = 0.0,
 				     float param5 = 0.0, float param6 = 0.0, float param7 = 0.0)
 	{
 		reset_last_sent();