dt-bindings: power: supply: qcom,pm8941: use regulator schema for child node

The 'usb-otg-vbus' child node is a regulator so reference the regulator
schema for proper evaluation.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/devicetree/bindings/power/supply/qcom,pm8941-charger.yaml

@@ -121,7 +121,7 @@ properties:
     description: Reference to the regulator supplying power to the USB_OTG_IN pin.
 
   otg-vbus:
-    type: object
+    $ref: /schemas/regulator/regulator.yaml#
     description: |
       This node defines a regulator used to control the direction of VBUS voltage.
       Specifically whether to supply voltage to VBUS for host mode operation of the OTG port,