dt-bindings: input: iqs7222: Use central 'linux,code' definition

Channel events adopt the newly centralized 'linux,code' property;
slider events should too.

Fixes: 8ac14d2c ("dt-bindings: input: Centralize 'linux,code' definition")
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220710024713.17275-1-jeff@labundy.comSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Documentation/devicetree/bindings/input/azoteq,iqs7222.yaml

@@ -566,14 +566,13 @@ patternProperties:
     patternProperties:
       "^event-(press|tap|(swipe|flick)-(pos|neg))$":
         type: object
+        $ref: input.yaml#
         description:
           Represents a press or gesture (IQS7222A only) event reported by
           the slider.
 
         properties:
-          linux,code:
-            $ref: /schemas/types.yaml#/definitions/uint32
-            description: Numeric key code associated with the event.
+          linux,code: true
 
           azoteq,gesture-max-ms:
             multipleOf: 4