dt-bindings: extcon: ptn5150: Make 'vbus-gpios' optional

The PTN5150 chip can be used in hardware designs with only reporting of
USB Type-C connection, without the VBUS control.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Vijai Kumar K <vijaikumar.kanagarajan@gmail.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

Documentation/devicetree/bindings/extcon/extcon-ptn5150.yaml

@@ -32,13 +32,13 @@ properties:
 
   vbus-gpios:
     description:
-      GPIO pin (output) used to control VBUS.
+      GPIO pin (output) used to control VBUS. If skipped, no such control
+      takes place.
 
 required:
   - compatible
   - interrupts
   - reg
-  - vbus-gpios
 
 additionalProperties: false