dt-bindings: net: wireless: mt76: add bindings for MT7981

Add mediatek,mt7981-wmac compatible string entry.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

Documentation/devicetree/bindings/net/wireless/mediatek,mt76.yaml

@@ -28,6 +28,7 @@ properties:
       - mediatek,mt76
       - mediatek,mt7628-wmac
       - mediatek,mt7622-wmac
+      - mediatek,mt7981-wmac
       - mediatek,mt7986-wmac
 
   reg: