dt-bindings: interrupt-controller: brcm,bcm7120-l2-intc: Fix 'brcm,int-fwd-mask' differing type

'brcm,int-fwd-mask' is also defined in brcm,bcm7038-l1-intc.yaml as a
'uint32-array', so unify the type definition.
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230125221423.3058221-1-robh@kernel.orgSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/interrupt-controller/brcm,bcm7120-l2-intc.yaml

@@ -109,7 +109,8 @@ properties:
       for system suspend/resume.
 
   brcm,int-fwd-mask:
-    $ref: /schemas/types.yaml#/definitions/uint32
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    maxItems: 1
     description: >
       if present, a bit mask to configure the interrupts which have a mux gate,
       typically UARTs. Setting these bits will make their respective interrupt