dt-bindings: iio: adc: ad7380: add AD7389-4

Add compatible and quirks for AD7389-4. This is essentially the same as
AD7380-4 but instead of having no internal reference, it has no external
reference voltage supply.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250401-iio-ad7380-add-ad7389-4-v1-1-23d2568aa24f@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/adi,ad7380.yaml

@@ -25,6 +25,7 @@ description: |
   * https://www.analog.com/en/products/ad7386-4.html
   * https://www.analog.com/en/products/ad7387-4.html
   * https://www.analog.com/en/products/ad7388-4.html
+  * https://www.analog.com/en/products/ad7389-4.html
   * https://www.analog.com/en/products/adaq4370-4.html
   * https://www.analog.com/en/products/adaq4380-4.html
   * https://www.analog.com/en/products/adaq4381-4.html
@@ -49,6 +50,7 @@ properties:
       - adi,ad7386-4
       - adi,ad7387-4
       - adi,ad7388-4
+      - adi,ad7389-4
       - adi,adaq4370-4
       - adi,adaq4380-4
       - adi,adaq4381-4
@@ -213,6 +215,15 @@ allOf:
       properties:
         refin-supply: false
 
+  # adi,ad7389-4 is internal reference only
+  - if:
+      properties:
+        compatible:
+          const: adi,ad7389-4
+    then:
+      properties:
+        refio-supply: false
+
   # adaq devices need more supplies and using channel to declare gain property
   # only applies to adaq devices
   - if: