Rover: replace message indicating that initialisation has completed

Rover/system.cpp

@@ -166,8 +166,6 @@ void Rover::startup_ground(void)
     // we don't want writes to the serial port to cause us to pause
     // so set serial ports non-blocking once we are ready to drive
     serial_manager.set_blocking_writes_all(false);
-
-    gcs().send_text(MAV_SEVERITY_INFO, "Ready to drive");
 }
 
 // update the ahrs flyforward setting which can allow