dt-bindings: extcon: maxim,max77843: fix ports type

The "ports" property can contain multiple ports as name suggests, so it
should be using "ports" type from device graphs.
Reported-by: Rob Herring <robh@kernel.org>
Fixes: 9729cad0 ("dt-bindings: extcon: maxim,max77843: Add MAX77843 bindings")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220310073258.24060-1-krzysztof.kozlowski@canonical.com

Documentation/devicetree/bindings/extcon/maxim,max77843.yaml

@@ -25,7 +25,7 @@ properties:
     $ref: /schemas/connector/usb-connector.yaml#
 
   ports:
-    $ref: /schemas/graph.yaml#/properties/port
+    $ref: /schemas/graph.yaml#/properties/ports
     description:
       Any connector to the data bus of this controller should be modelled using
       the OF graph bindings specified