ASoC: dt-bindings: qcom,wcd934x: Describe slim-ifc-dev

The "slim-ifc-dev" property should not be just "true", because it allows
any type.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230206180805.6621-2-krzysztof.kozlowski@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/qcom,wcd934x.yaml

@@ -28,7 +28,9 @@ properties:
     description: GPIO spec for reset line to use
     maxItems: 1
 
-  slim-ifc-dev: true
+  slim-ifc-dev:
+    description: IFC device interface
+    $ref: /schemas/types.yaml#/definitions/phandle
 
   clocks:
     maxItems: 1