dt-bindings: regulator: Fix node descriptions in uniphier-regulator example

Drop a parent node of the regulator as it is not directly necessary.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221213082449.2721-5-hayashi.kunihiko@socionext.com
Signed-off-by: Rob Herring <robh@kernel.org>