dt-bindings: soc: rockchip: grf: add rockchip,rk3288-dp-phy.yaml

Add new converted rockchip,rk3288-dp-phy.yaml to grf.yaml file.

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
[dropped the unrelated blank line removals that didn't apply]
Link: https://lore.kernel.org/r/5759c6e1-9c89-4cb2-dd57-83a8db09f547@gmail.com


Signed-off-by: Heiko Stuebner <heiko@sntech.de>