dt-bindings: Add device tree support for Winsen MHZ19B CO2 sensor

Add device tree support for Winsen MHZ19B sensor.

Signed-off-by: Gyeyoung Baek <gye976@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250423194100.53934-3-gye976@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/chemical/winsen,mhz19b.yaml

@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/chemical/winsen,mhz19b.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MHZ19B CO2 sensor
+
+maintainers:
+  - Gyeyoung Baek <gye976@gmail.com>
+
+properties:
+  compatible:
+    const: winsen,mhz19b
+
+  vin-supply:
+    description: Regulator that provides power to the sensor
+
+required:
+  - compatible
+  - vin-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    serial {
+      co2-sensor {
+        compatible = "winsen,mhz19b";
+        vin-supply = <&vdd>;
+      };
+    };
+...