dt-bindings: arm: bcm: document Netgear RAXE500 binding

One more BCM4908 based device.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

Documentation/devicetree/bindings/arm/bcm/brcm,bcm4908.yaml

@@ -29,6 +29,7 @@ properties:
         items:
           - enum:
               - asus,gt-ac5300
+              - netgear,raxe500
           - const: brcm,bcm4908
 
       - description: BCM49408 based boards