dt-bindings: reset: renesas,rzg2l-usbphy-ctrl: Document USB VBUS regulator

The VBUS enable can be controlled by the VBOUT bit of the VBUS control
register. This register is part of usbphy-ctrl IP.

Document the USB VBUS regulator object.
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20240702180032.207275-2-biju.das.jz@bp.renesas.comSigned-off-by: Philipp Zabel <p.zabel@pengutronix.de>

Documentation/devicetree/bindings/reset/renesas,rzg2l-usbphy-ctrl.yaml

@@ -42,6 +42,12 @@ properties:
       0 = Port 1 Phy reset
       1 = Port 2 Phy reset
 
+  regulator-vbus:
+    type: object
+    description: USB VBUS regulator
+    $ref: /schemas/regulator/regulator.yaml#
+    unevaluatedProperties: false
+
 required:
   - compatible
   - reg
@@ -49,6 +55,7 @@ required:
   - resets
   - power-domains
   - '#reset-cells'
+  - regulator-vbus
 
 additionalProperties: false
 
@@ -64,4 +71,7 @@ examples:
         resets = <&cpg R9A07G044_USB_PRESETN>;
         power-domains = <&cpg>;
         #reset-cells = <1>;
+        regulator-vbus {
+            regulator-name = "vbus";
+        };
     };