When system shuts down, RTC enable eosc calibration feature to save power. Then coreboot RTC driver needs to call rtc_enable_dcxo function at every boot to switch RTC clock source to dcxo. BUG=b:128467245 BRANCH=none TEST=Boots correctly on Kukui Change-Id: Iee21e7611df8959cbbc63b6e6655cfb462147748 Signed-off-by: Ran Bi <ran.bi@mediatek.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/32339 Tested-by: build bot (Jenkins) <no-reply@coreboot.org> Reviewed-by: Julius Werner <jwerner@chromium.org>