Hid timer function parameters in a macro (#3311)

src/map/mapreg.cpp

@@ -264,8 +264,7 @@ static void script_save_mapreg(void)
 /**
  * Timer event to auto-save permanent variables.
  */
-static int script_autosave_mapreg(int tid, unsigned int tick, int id, intptr_t data)
-{
+static TIMER_FUNC(script_autosave_mapreg){
 	script_save_mapreg();
 	return 0;
 }