chore(demos): add common entry for lv_demos (#4610)

Signed-off-by: XiaoweiYan <yanxiaowei@xiaomi.com>
Signed-off-by: YanXiaowei <yanxiaowei@xiaomi.com>
Co-authored-by: XiaoweiYan <yanxiaowei@xiaomi.com>

src/lv_init.h

@@ -35,17 +35,11 @@ extern "C" {
 void lv_init(void);
 
 
-#if LV_ENABLE_GLOBAL_CUSTOM || LV_USE_STDLIB_MALLOC == LV_STDLIB_BUILTIN
-
 /**
  * Deinit the 'lv' library
- * Currently only implemented when not using custom allocators,
- * or using custom 'lv_global'.
  */
 void lv_deinit(void);
 
-#endif
-
 /**
  * Returns whether the 'lv' library is currently initialized
  */