ArduSub: move AP_PARM_KEY_DUMP function up to AP_Vehicle base class

Common to all vehicles now, including Tracker

ArduSub/system.cpp

@@ -192,10 +192,6 @@ void Sub::init_ardupilot()
 
     // flag that initialisation has completed
     ap.initialised = true;
-
-#if AP_PARAM_KEY_DUMP
-    AP_Param::show_all(hal.console, true);
-#endif
 }