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

Prior to adding dt-bindings for SoC-dependent controllers, rename the
thermal node and its parent node to the generic names in the example.

And drop a parent node of the thermal-sensor  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/20221213082449.2721-7-hayashi.kunihiko@socionext.com


Signed-off-by: Rob Herring <robh@kernel.org>