add AC State change callback

src/user_code.hpp

@@ -21,6 +21,7 @@ void user_init();
 void user_loop();
 void virtual_interrupt_user_callback(int pin, int state);
 void pwm_changed_user_callback(int pin);
+void ac_changed_user_callback(int mode, int temperature, int fan_speed);
 void timer_tick_callback();
 void timer1_callback();
 void bt0PopCallback(void *ptr);