The ARM PMU and ARM architected timer nodes are part of ARM CPU design
therefore they should not be inside the soc node.  This also fixes DTC
W=1 warnings like:

    arch/arm/boot/dts/exynos3250.dtsi:106.21-135.5:
        Warning (simple_bus_reg): /soc/fixed-rate-clocks: missing or empty reg/ranges property
    arch/arm/boot/dts/exynos3250.dtsi:676.7-680.5:
        Warning (simple_bus_reg): /soc/pmu: missing or empty reg/ranges property
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>