dt-bindings: iio: humidity: Add TI HDC20x0 support

Add device tree bindings for HDC2010/HDC2080 family of humidity and
temperature sensors.
Signed-off-by: Eugene Zaikonnikov <ez@norphonic.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/humidity/ti,hdc2010.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/humidity/ti,hdc2010.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: HDC2010/HDC2080 humidity and temperature iio sensors
+
+maintainers:
+  - Eugene Zaikonnikov <ez@norophonic.com>
+
+description: |
+  Relative humidity and tempereature sensors on I2C bus
+
+  Datasheets are available at:
+    http://www.ti.com/product/HDC2010/datasheet
+    http://www.ti.com/product/HDC2080/datasheet
+
+properties:
+  compatible:
+    enum:
+      - ti,hdc2010
+      - ti,hdc2080
+
+  vdd-supply:
+    maxItems: 1
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    i2c0 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      humidity@40 {
+          compatible = "ti,hdc2010";
+          reg = <0x40>;
+      };
+    };