dt-bindings: iio: temperature: ltc2983: document power supply

Add a property for the VDD power supply regulator.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240404-ltc2983-misc-improv-v5-1-c1f58057fcea@analog.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml

@@ -57,6 +57,8 @@ properties:
   interrupts:
     maxItems: 1
 
+  vdd-supply: true
+
   adi,mux-delay-config-us:
     description: |
       Extra delay prior to each conversion, in addition to the internal 1ms
@@ -460,6 +462,7 @@ required:
   - compatible
   - reg
   - interrupts
+  - vdd-supply
 
 additionalProperties: false
 
@@ -489,6 +492,7 @@ examples:
             #address-cells = <1>;
             #size-cells = <0>;
 
+            vdd-supply = <&supply>;
             interrupts = <20 IRQ_TYPE_EDGE_RISING>;
             interrupt-parent = <&gpio>;