arm64: dts: exynos: Remove unneeded address space mapping for soc node

Remove the address space mapping between root and soc nodes to fix
DTC warnings in Exynos5433 and Exynos7 like:

    arch/arm64/boot/dts/exynos/exynos5433-tm2.dtb:
        Warning (unit_address_vs_reg): /soc: node has a reg or ranges property, but no unit name

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>