dt-bindings: usb: meson-g12a-usb: Validate DWC2/DWC3 sub-nodes

Amlogic G12A USB DT sub-nodes are supposed to be compatible with the
generic DWC USB2 and USB3 devices. Since now we've got DT schemas for
both of the later IP cores let's make sure that the Amlogic G12A USB
DT nodes are fully evaluated including the DWC sub-nodes.
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201210090944.16283-17-Sergey.Semin@baikalelectronics.ruSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/amlogic,meson-g12a-usb-ctrl.yaml

@@ -79,7 +79,9 @@ properties:
 
 patternProperties:
   "^usb@[0-9a-f]+$":
-    type: object
+    oneOf:
+      - $ref: dwc2.yaml#
+      - $ref: snps,dwc3.yaml#
 
 additionalProperties: false