ARM: dts: exynos: Add CPU cooling in Exynos4412 Origen

Add missing cooling devices for CPU thermal zones in Exynos4412 Origen
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/20200830135200.24304-28-krzk@kernel.org