dt-bindings: arm: bcm2835: Add Raspberry Pi 4 to DT schema

Add new Raspberry Pi 4 to DT schema.
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Acked-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/arm/bcm/bcm2835.yaml

@@ -15,6 +15,12 @@ properties:
     const: '/'
   compatible:
     oneOf:
+      - description: BCM2711 based Boards
+        items:
+          - enum:
+              - raspberrypi,4-model-b
+          - const: brcm,bcm2711
+
       - description: BCM2835 based Boards
         items:
           - enum: