Update script.c

- Update instance_enter DEF
- Remove instance_enter2 DEF

src/map/script.c

@@ -19088,8 +19088,7 @@ struct script_function buildin_func[] = {
 	BUILDIN_DEF(instance_create,"s"),
 	BUILDIN_DEF(instance_destroy,"?"),
 	BUILDIN_DEF(instance_id,""),
-	BUILDIN_DEF(instance_enter,"s"),
-	BUILDIN_DEF(instance_enter2,"sii"),
+	BUILDIN_DEF(instance_enter,"s??"),
 	BUILDIN_DEF(instance_npcname,"s?"),
 	BUILDIN_DEF(instance_mapname,"s?"),
 	BUILDIN_DEF(instance_warpall,"sii?"),