joystick UI: drop dead do_render label

The wake-path goto was replaced with _pending_render + continue
during the loop refactor; the label became unreachable. gcc
flagged it with -Wunused-label.

zephcore/helpers/ui-joystick/joystick_ui_task.cpp

@@ -819,7 +819,6 @@ void JoystickUITask::loop()
 		_pending_render = true;
 	}
 
-do_render:
 	if (!_display.isOn() || !_curr) {
 		return;
 	}