dt-bindings: display: synopsys,dw-hdmi: drop ref from reg-io-width

reg-io-width is a standard property, so no need for defining its type
with $ref.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20220823101031.387082-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/display/bridge/synopsys,dw-hdmi.yaml

@@ -26,7 +26,6 @@ properties:
   reg-io-width:
     description:
       Width (in bytes) of the registers specified by the reg property.
-    $ref: /schemas/types.yaml#/definitions/uint32
     enum: [1, 4]
     default: 1