dt-bindings: pinctrl: airoha: Add missing gpio-ranges property

Introduce leftover gpio-ranges property for Airoha EN7581 pinctrl binding

Fixes: d0c15cb ("dt-bindings: pinctrl: airoha: Add EN7581 pinctrl")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/20250307-en7581-gpio-range-v1-1-de1262105428@kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/airoha,en7581-pinctrl.yaml

@@ -24,6 +24,9 @@ properties:
   '#gpio-cells':
     const: 2
 
+  gpio-ranges:
+    maxItems: 1
+
   interrupt-controller: true
 
   '#interrupt-cells':