dt-bindings: iio: adc: mcp3911: add microchip,data-ready-hiz entry

The Data Ready Output Pin is either hard wired to work as high
impedance or push-pull. Make it configurable.
Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20220815061625.35568-8-marcus.folkesson@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/microchip,mcp3911.yaml

@@ -36,6 +36,13 @@ properties:
     description: IRQ line of the ADC
     maxItems: 1
 
+  microchip,data-ready-hiz:
+    description:
+      Data Ready Pin Inactive State Control
+      true = The DR pin state is high-impedance
+      false = The DR pin state is logic high
+    type: boolean
+
   microchip,device-addr:
     description: Device address when multiple MCP3911 chips are present on the same SPI bus.
     $ref: /schemas/types.yaml#/definitions/uint32