dt-bindings: display: rockchip: dw-hdmi: Make unwedge pinctrl optional

None of the upstream device tree files has a "unwedge" pinctrl
specified. Make it optional.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Rob Herring <robh@kernel.org>
Tested-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220422072841.2206452-16-s.hauer@pengutronix.de

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

@@ -89,6 +89,7 @@ properties:
       The unwedge pinctrl entry shall drive the DDC SDA line low. This is
       intended to work around a hardware errata that can cause the DDC I2C
       bus to be wedged.
+    minItems: 1
     items:
       - const: default
       - const: unwedge