dt-bindings: extcon: ptn5150: add child node port

Add child node 'port' to allow connect to usb controller to do role-switch
if id pin of ptn5150 have not connected to chip's usb ID function pin.

Fix below warning:
arch/arm64/boot/dts/freescale/imx8mn-var-som-symphony.dtb: typec@3d: 'port' does not match any of the regexes: 'pinctrl-[0-9]+'
        from schema $id: http://devicetree.org/schemas/extcon/extcon-ptn5150.yaml

Link: https://lore.kernel.org/lkml/20240820143911.444048-1-Frank.Li@nxp.com/


Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>