dt-bindings: display: rockchip: dw-hdmi: Add compatible for rk3568 HDMI

Define a new compatible for rk3568 HDMI.
This version of HDMI hardware block needs two new clocks hclk_vio and hclk
to provide phy reference clocks.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220422072841.2206452-9-s.hauer@pengutronix.de

Documentation/devicetree/bindings/display/rockchip/rockchip,dw-hdmi.yaml

@@ -23,6 +23,7 @@ properties:
       - rockchip,rk3288-dw-hdmi
       - rockchip,rk3328-dw-hdmi
       - rockchip,rk3399-dw-hdmi
+      - rockchip,rk3568-dw-hdmi
 
   reg-io-width:
     const: 4