This commit adds support for using the RTC I2C peripheral on the ULP
RISC-V core for esp32s2 and esp32s3. It also adds an example to demonstrate the
usage of the RTC I2C peripheral.
This commit also modifies the rtc_i2c register structure files to enable
the use of bitfields in the ULP RISC-V RTC I2C driver.
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
