dt-bindings: usb: dwc3: Add snps,ulpi-ext-vbus-drv quirk

Some ULPI USB PHYs do not support an internal vBus supply, to drive the
CPEN pin properly, it requires configuration of the ULPI DRVVBUSEXTERNAL
bit of the USB ULPI PHY OTG_CTRL register.

Added 'snps,ulpi-ext-vbus-drv' DT property to configure the USB2 PHY to
drives VBUS with an external supply.

When the ULPIEXTVBUSDRV bit is set to '1' in the Global USB2 PHY
Configuration registers, PHY drive vBus with an external 5V supply source.
Signed-off-by: Piyush Mehta <piyush.mehta@amd.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230215093146.5812-2-piyush.mehta@amd.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -260,6 +260,14 @@ properties:
       of resume. This option is to support certain legacy ULPI PHYs.
     type: boolean
 
+  snps,ulpi-ext-vbus-drv:
+    description:
+      Some ULPI USB PHY does not support internal VBUS supply, and driving
+      the CPEN pin, requires the configuration of the ulpi DRVVBUSEXTERNAL
+      bit. When set, the xhci host will configure the USB2 PHY drives VBUS
+      with an external supply.
+    type: boolean
+
   snps,is-utmi-l1-suspend:
     description:
       True when DWC3 asserts output signal utmi_l1_suspend_n, false when