dt-bindings: usb: qcom,dwc3: Add binding for SDX55

Add devicetree binding for SDX55 USB controller based on Qcom designware
IP.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: devicetree@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Acked-by: NFelipe Balbi <balbi@kernel.org>
Signed-off-by: NManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210118051005.55958-2-manivannan.sadhasivam@linaro.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/qcom,dwc3.yaml

@@ -17,6 +17,7 @@ properties:
           - qcom,msm8998-dwc3
           - qcom,sc7180-dwc3
           - qcom,sdm845-dwc3
+          - qcom,sdx55-dwc3
       - const: qcom,dwc3
 
   reg: