dt-bindings: hwmon: ina2xx: Add label property

Add a label property to allow a custom name to be used for identifying
a device on the board. This is useful when multiple devices are present on
the same board. Similar change was done by commit ffae65fb
("dt-bindings: spi: spi-cadence: Add label property").
Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/6f3c57d08984c1978569d3918cb38eb295c0c67d.1703077926.git.michal.simek@amd.comSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/ti,ina2xx.yaml

@@ -32,6 +32,9 @@ properties:
   reg:
     maxItems: 1
 
+  label:
+    description: A descriptive name for this device.
+
   shunt-resistor:
     description:
       Shunt resistor value in micro-Ohm.
@@ -77,6 +80,7 @@ examples:
         power-sensor@44 {
             compatible = "ti,ina220";
             reg = <0x44>;
+            label = "vdd_3v0";
             shunt-resistor = <1000>;
             vs-supply = <&vdd_3v0>;
         };