phy: samsung,dp-video-phy: deprecate syscon phandle

The DisplayPort phy is actually part of the Power Management Unit system
controller, thus it should be its child, instead of sibling node with
syscon phandle.

Acked-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20230127194057.186458-5-krzysztof.kozlowski@linaro.org


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>