Documentation/devicetree/bindings/usb/dwc3-st.txt: update usb-drd.yaml reference

Changeset b0864e1a ("dt-bindings: usb: Convert generic USB properties to DT schemas")
renamed: Documentation/devicetree/bindings/usb/generic.txt
to: Documentation/devicetree/bindings/usb/usb-drd.yaml.

Update its cross-reference accordingly.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/43d5049a8ed688980bee12ecf18ef9937981de39.1610605373.git.mchehab+huawei@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>