dt-bindings: usb: generic-ehci: Add HPE GXP ehci binding

Add hpe,gxp-ehci to the generic-ehci list. This is to
enable the device tree.
Signed-off-by: Nick Hawkins <nick.hawkins@hpe.com>
Link: https://lore.kernel.org/r/20220421192132.109954-9-nick.hawkins@hpe.comAcked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/generic-ehci.yaml

@@ -55,6 +55,7 @@ properties:
               - brcm,bcm7420-ehci
               - brcm,bcm7425-ehci
               - brcm,bcm7435-ehci
+              - hpe,gxp-ehci
               - ibm,476gtr-ehci
               - nxp,lpc1850-ehci
               - qca,ar7100-ehci