dt-bindings: thermal: generic-adc: reference thermal-sensor schema

Device is a thermal sensor and it requires '#thermal-sensor-cells', so
reference the thermal-sensor.yaml to simplify it and bring the
common definition of '#thermal-sensor-cells' property.

Acked-by: Conor Dooley <[e-mail]>
Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Daniel Lezcano <[e-mail]>

Documentation/devicetree/bindings/thermal/generic-adc-thermal.yaml

···
   sensor resistor. The voltage read across the sensor is mapped to
   temperature using voltage-temperature lookup table.
 
+$ref: thermal-sensor.yaml#
+
 properties:
   compatible:
     const: generic-adc-thermal
···
 
 required:
   - compatible
-  - '#thermal-sensor-cells'
   - io-channels
   - io-channel-names
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |