added a messageplayer prototype for ros

src/platforms/nuttx/px4_messages/px4_rc_channels.h

@@ -0,0 +1,26 @@
+#include <uORB/uORB.h>
+#include <uORB/topics/rc_channels.h>
+#include "platforms/px4_message.h"
+
+#pragma once
+namespace px4
+{
+
+class  px4_rc_channels :
+	public PX4Message<rc_channels_s>
+{
+public:
+	px4_rc_channels() :
+		PX4Message<rc_channels_s>()
+	{}
+
+	px4_rc_channels(rc_channels_s msg) :
+		PX4Message<rc_channels_s>(msg)
+	{}
+
+	~px4_rc_channels() {}
+
+	PX4TopicHandle handle() {return (PX4TopicHandle)ORB_ID(rc_channels);}
+};
+
+}