dt-bindings: net: ethernet-controller: drop redundant type from label

dtschema defines label as string, so $ref in other bindings is
redundant.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/ethernet-controller.yaml

@@ -14,7 +14,6 @@ properties:
     pattern: "^ethernet(@.*)?$"
 
   label:
-    $ref: /schemas/types.yaml#/definitions/string
     description: Human readable label on a port of a box.
 
   local-mac-address: