dt-bindings: net: can: nxp,sja1000: drop ref from reg-io-width

reg-io-width is a standard property, so no need for defining its type
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/all/20220823101011.386970-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Documentation/devicetree/bindings/net/can/nxp,sja1000.yaml

@@ -34,7 +34,6 @@ properties:
     maxItems: 1
 
   reg-io-width:
-    $ref: /schemas/types.yaml#/definitions/uint32
     description: I/O register width (in bytes) implemented by this device
     default: 1
     enum: [ 1, 2, 4 ]