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.
This commit refactors the ulp component.
Files are now divided based on type of ulp, viz., fsm or risc-v.
Files common to both are maintained in the ulp_common folder.
This commit also adds menuconfig options for ULP within the ulp
component instead of presenting target specific configuations for ulp.
