dt-bindings: display: hdmi-connector: add hdmi-pwr supply

Follow the dp-connector example and add hdmi-pwr supply to drive the 5V
pin of the HDMI connector (together with some simple glue logic possibly
attached to the connector).

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230531000259.3758235-2-dmitry.baryshkov@linaro.org