ARM: dts: exynos: Disable unused buck10 regulator on Odroid HC1 board

The eMMC memory on Odroid XU3/XU4 boards is supplied by two regulators
LDO18 and buck10 (and LDO13 for the host interface).

However the Odroid HC1 board does not have eMMC connector so this
regulator does not have to be always on.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>