ARM: dts: exynos: Remove unnecessary address/size properties in Midas boards

The children of regulators node do not have reg/ranges properties.  Move the
children up one level, get rid of regulators node and remove
address-cells and size-cells properties.  This fixes warnings for
Exynos4412 Midas family boards:

    arch/arm/boot/dts/exynos4412-i9300.dtb: Warning (avoid_unnecessary_addr_size):
        /regulators: unnecessary #address-cells/#size-cells without "ranges" or child "reg" property
    arch/arm/boot/dts/exynos4412-i9305.dtb: Warning (avoid_unnecessary_addr_size):
        /regulators: unnecessary #address-cells/#size-cells without "ranges" or child "reg" property
    arch/arm/boot/dts/exynos4412-n710x.dtb: Warning (avoid_unnecessary_addr_size):
        /regulators: unnecessary #address-cells/#size-cells without "ranges" or child "reg" property

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