dt-bindings: phy: samsung,exynos-hdmi-phy: convert to dtschema

Convert the Exynos HDMI PHY bindings to DT schema format and put them
next to other PHYs.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220208171823.226211-4-krzysztof.kozlowski@canonical.com