esp_reset_reason_set_hint() replacement by NVS flag (ESP32-S2)

[T94T]

Since esp_reset_reason_set_hint() is not working/supported anymore (see: espressif/esp-idf#7230) I decided to rewrite the corresponding code using NVS storage instead.

Please note that this pull request does not work at the moment. There is still a compilation error:

tinyuf2/lib/esp-idf/components/nvs_flash/src/nvs_platform.hpp:31:10: fatal error: freertos/FreeRTOS.h: No such file or directory
 #include "freertos/FreeRTOS.h"
          ^~~~~~~~~~~~~~~~~~~~~

I hope someone can fix this.

[T94T]

will prepare the pull request again.

[hathach]

@T94T I dived a bit into this, there is no need for using NVS, the reason hint is still accessible within stage2 bootloader. IDF just slightly changes the reset reason for esp_restart(). I will make an PR to correct this.