dt-bindings: usb: dwc2: fix bindings for amlogic, meson-gxbb-usb

The amlogic,meson-gxbb-usb compatible needs snps,dwc2 aswell like other
Amlogic SoC.

Fixes: f3ca745d ("dt-bindings: usb: Convert DWC2 bindings to json-schema")
Reviewed-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/usb/dwc2.yaml

@@ -44,14 +44,11 @@ properties:
       - const: lantiq,arx100-usb
       - const: lantiq,xrx200-usb
       - items:
-          - const: amlogic,meson8-usb
-          - const: snps,dwc2
-      - items:
-          - const: amlogic,meson8b-usb
-          - const: snps,dwc2
-      - const: amlogic,meson-gxbb-usb
-      - items:
-          - const: amlogic,meson-g12a-usb
+          - enum:
+            - amlogic,meson8-usb
+            - amlogic,meson8b-usb
+            - amlogic,meson-gxbb-usb
+            - amlogic,meson-g12a-usb
           - const: snps,dwc2
       - const: amcc,dwc-otg
       - const: snps,dwc2