dt-bindings: input: exc3000: support power supply regulators

Add power supply regulator support to the exc3000 devices.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230707131042.10795-1-mike.looijmans@topic.nl


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>