dt-bindings: thermal: sprd: 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.

Reviewed-by: Baolin Wang <[e-mail]>
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/sprd-thermal.yaml

···
   - Baolin Wang <[e-mail]>
   - Chunyan Zhang <[e-mail]>
 
+$ref: thermal-sensor.yaml#
+
 properties:
   compatible:
     const: sprd,ums512-thermal
···
   - clock-names
   - nvmem-cells
   - nvmem-cell-names
-  - "#thermal-sensor-cells"
   - "#address-cells"
   - "#size-cells"
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |