dt-bindings: iio: adc: ti,adc161s626 yaml conversion.

Simple conversion for this ADC driver.  Note that I haven't put
limits on the spi-max-sampling-frequency because the adc161s626
doesn't state one clearly defined value.

Added the #io-channel-cells property to allow for consumers.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Matt Ranostay <matt.ranostay@konsulko.com>
Cc: Matt Ranostay <matt.ranostay@konsulko.com>
Link: https://lore.kernel.org/r/20200809111753.156236-6-jic23@kernel.org

Documentation/devicetree/bindings/iio/adc/ti,adc161s626.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/ti,adc161s626.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments ADC141S626 and ADC161S626 ADCs
+
+maintainers:
+  - Matt Ranostay <matt.ranostay@konsulko.com>
+
+description: |
+  Single channel 14/16bit differential ADCs
+
+properties:
+  compatible:
+    enum:
+      - ti,adc141s626
+      - ti,adc161s626
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency: true
+
+  vdda-supply: true
+
+  "#io-channel-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        adc@0 {
+            compatible = "ti,adc161s626";
+            vdda-supply = <&vdda_fixed>;
+            reg = <0>;
+            spi-max-frequency = <4300000>;
+            #io-channel-cells = <1>;
+        };
+    };
+...

Documentation/devicetree/bindings/iio/adc/ti-adc161s626.txt

-* Texas Instruments ADC141S626 and ADC161S626 chips
-
-Required properties:
- - compatible: Should be "ti,adc141s626" or "ti,adc161s626"
- - reg: spi chip select number for the device
- - vdda-supply: supply voltage to VDDA pin
-
-Recommended properties:
- - spi-max-frequency: Definition as per
-		Documentation/devicetree/bindings/spi/spi-bus.txt
-
-Example:
-adc@0 {
-	compatible = "ti,adc161s626";
-	vdda-supply = <&vdda_fixed>;
-	reg = <0>;
-	spi-max-frequency = <4300000>;
-};