dt-bindings: iio: dac: ad5686: Add an entry for AD5337

AD5337 belongs to the same family as the AD5338.

The difference is that the AD5337 has 8-bit resolution instead of 10-bit.

Add a compatible entry for AD5337.
Signed-off-by: NFabio Estevam <festevam@gmail.com>
Acked-by: NKrzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221130182632.3856675-1-festevam@gmail.comSigned-off-by: NJonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/dac/adi,ad5686.yaml

@@ -33,6 +33,7 @@ properties:
       - description: I2C devices
         enum:
           - adi,ad5311r
+          - adi,ad5337r
           - adi,ad5338r
           - adi,ad5671r
           - adi,ad5675r