Also remove PM_USE_RTC_TIMER_REF in esp32s2, since this option is only used in FRC implementation of esp_timer. Closes https://github.com/espressif/esp-idf/issues/4991
Also remove PM_USE_RTC_TIMER_REF in esp32s2, since this option is only used in FRC implementation of esp_timer. Closes https://github.com/espressif/esp-idf/issues/4991