ARM: dts: use pwm-fan device as a cooling device for exynos4412-odroidu3

With those bindings it is possible to use pwm-fan device available in
Odroid U3 as a cooling device.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Acked-by: Eduardo Valentin <edubezval@gmail.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>