Wait 200ms before actually starting the display thread

Give some time to the underlying layer to prepare the splash before trying to access it
Better fix: use a semaphore

TODO: there could be similar use cases when the resources that must be displayed are not yet ready.

Reason:
cores 2.7.x like to crash on
lv_fs_res_t lv_fs_read(lv_fs_file_t * file_p, void * buf, uint32_t btr, uint32_t * br)

Author: facchinm

src/Braccio++.cpp

@@ -409,6 +409,7 @@ void BraccioClass::lvgl_init()
 
 void BraccioClass::display_thread_func()
 {
+  delay(200);
   for(;;)
   {
     lv_task_handler();