dt-bindings: iio/adc: qcom,spmi-iadc: document PM8226 compatible

Document the compatible for the IADC used on PM8226.
Signed-off-by: NRayyan Ansari <rayyan@ansari.sh>
Acked-by: NKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221228230421.56250-5-rayyan@ansari.shSigned-off-by: NJonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.yaml

@@ -20,6 +20,7 @@ properties:
   compatible:
     items:
       - enum:
+          - qcom,pm8226-iadc
           - qcom,pm8941-iadc
       - const: qcom,spmi-iadc