dt-bindings: net: mediatek: add WED RX binding for MT7981 eth driver

Add compatible string for mediatek,mt7981-wed as MT7981 also supports
RX WED just like MT7986, but needs a different firmware file.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/arm/mediatek/mediatek,mt7622-wed.yaml

@@ -20,6 +20,7 @@ properties:
     items:
       - enum:
           - mediatek,mt7622-wed
+          - mediatek,mt7981-wed
           - mediatek,mt7986-wed
       - const: syscon