ARM: dts: exynos: Fix missing empty reg/ranges property regulators on Trats

Remove the regulators node entirely because its children do not have any
unit addresses.  This fixes DTC warning:

    Warning (simple_bus_reg): /regulators/regulator-0: missing or empty reg/ranges property

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