update:lvgl8 LV_USE_PERF_MONITOR config

components/lvgl8/lv_conf.h

@@ -286,7 +286,9 @@
  *-----------*/
 
 /*1: Show CPU usage and FPS count*/
+#ifndef LV_USE_PERF_MONITOR
 #define LV_USE_PERF_MONITOR 0
+#endif
 #if LV_USE_PERF_MONITOR
     #define LV_USE_PERF_MONITOR_POS LV_ALIGN_BOTTOM_RIGHT
 #endif