ARM: dts: exynos: Add CPU cooling in Universal C210

Add missing cooling devices for CPU thermal zones in Exynos4210
Universal C310 board.  This allows to scale down CPU frequency (and
voltage) in case of thermal pressure.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20200830135200.24304-21-krzk@kernel.org