dt-bindings: thermal: loongson,ls2k-thermal: Fix binding check issues

Add the missing 'thermal-sensor-cells' property which is required for
every thermal sensor as it's used when using phandles.
And add the thermal-sensor.yaml reference.

In fact, it was a careless mistake when submitting the driver that
caused it to not work properly. So the fix is necessary, although it
will result in the ABI break.

Fixes: 72684d99 ("thermal: dt-bindings: add loongson-2 thermal")
Cc: Yinbo Zhu <zhuyinbo@loongson.cn>
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/6d69362632271ab0af9a5fbfa3bc46a0894f1d54.1700817227.git.zhoubinbin@loongson.cn

Documentation/devicetree/bindings/thermal/loongson,ls2k-thermal.yaml

@@ -10,6 +10,9 @@ maintainers:
   - zhanghongchen <zhanghongchen@loongson.cn>
   - Yinbo Zhu <zhuyinbo@loongson.cn>
 
+allOf:
+  - $ref: /schemas/thermal/thermal-sensor.yaml#
+
 properties:
   compatible:
     oneOf:
@@ -26,12 +29,16 @@ properties:
   interrupts:
     maxItems: 1
 
+  '#thermal-sensor-cells':
+    const: 1
+
 required:
   - compatible
   - reg
   - interrupts
+  - '#thermal-sensor-cells'
 
-additionalProperties: false
+unevaluatedProperties: false
 
 examples:
   - |
@@ -41,4 +48,5 @@ examples:
         reg = <0x1fe01500 0x30>;
         interrupt-parent = <&liointc0>;
         interrupts = <7 IRQ_TYPE_LEVEL_LOW>;
+        #thermal-sensor-cells = <1>;
     };