dt-bindings: imx-thermal: Add #thermal-sensor-cells property

This property is defined in thermal-sensor.yaml. Reference this file and
constraint '#thermal-sensor-cells' to 0 for imx-thermal.
Fixes the warning:
arch/arm/boot/dts/nxp/imx/imx6q-mba6a.dtb: tempmon:
 '#thermal-sensor-cells' does not match any of the regexes: 'pinctrl-[0-9]+'
 From schema: Documentation/devicetree/bindings/thermal/imx-thermal.yaml
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20231012080033.2715241-2-alexander.stein@ew.tq-group.com

Documentation/devicetree/bindings/thermal/imx-thermal.yaml

@@ -60,6 +60,9 @@ properties:
   clocks:
     maxItems: 1
 
+  "#thermal-sensor-cells":
+    const: 0
+
 required:
   - compatible
   - interrupts
@@ -67,6 +70,9 @@ required:
   - nvmem-cells
   - nvmem-cell-names
 
+allOf:
+  - $ref: thermal-sensor.yaml#
+
 additionalProperties: false
 
 examples:
@@ -104,5 +110,6 @@ examples:
              nvmem-cells = <&tempmon_calib>, <&tempmon_temp_grade>;
              nvmem-cell-names = "calib", "temp_grade";
              clocks = <&clks IMX6SX_CLK_PLL3_USB_OTG>;
+             #thermal-sensor-cells = <0>;
         };
     };