Merges https://github.com/espressif/esp-idf/pull/12093
fix(ll): remove FLAG_ATTR macro
Such kind of operator overload will not work because C++ thinks such overload is ambiguous and it still prefer the built-in one which accepts and returns integer. Manually force type conversion seems to be unavoidable.
update all struct headers to be more "standardized":
- bit fields are properly wrapped with struct
- bitwidth sum should be 32 within same struct, so that it's correctly padded with reserved bits
- bit field should be uint32_t
- typedef volatile struct xxx{} yyy;: xxx must exists. refer: https://github.com/espressif/esp-idf/pull/3199
added helper macros to force peripheral registers being accessed in 32 bitwidth
added a check script into ci
