Add node for clock controller of Samsung S5M8767 PMIC.  This provides
the 32768 Hz clock required by S3C RTC.  Except making the S3C RTC
working, this also fixes dtbs_check warnings:

  arch/arm/boot/dts/exynos4412-origen.dt.yaml: rtc@10070000: clocks: [[7, 346]] is too short
  arch/arm/boot/dts/exynos4412-origen.dt.yaml: rtc@10070000: clock-names: ['rtc'] is too short
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200830135200.24304-25-krzk@kernel.org