make esp_littlefs_info thread-safe, and a few corrections from upstream

[softhack007]

Hi,

This is a patch roll-up that we use in our project WLED - actually we cannot use newer IDF versions, because there are annoying bugs in the I2S and ADC/DAC drivers. So we still use your library.

We had problems with corrupted file systems. To overcome these problems, we've merged a few things in that seemed helpful. I'm submitting our version back to you, hoping that other projects might have a benefit.

Thanks for creating this great library, Frank.