dt-bindings: thermal: Fix node descriptions in uniphier-thermal example

Prior to adding dt-bindings for SoC-dependent controllers, rename the
thermal node and its parent node to the generic names in the example.

And drop a parent node of the thermal-sensor as it is not directly
necessary.

Signed-off-by: Kunihiko Hayashi <[e-mail]>
Acked-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Herring <[e-mail]>

Documentation/devicetree/bindings/thermal/socionext,uniphier-thermal.yaml

···
   - |
     // The UniPhier thermal should be a subnode of a "syscon" compatible node.
 
-    sysctrl@61840000 {
-        compatible = "socionext,uniphier-ld20-sysctrl",
-                     "simple-mfd", "syscon";
-        reg = <0x61840000 0x10000>;
-
-        pvtctl: thermal {
-            compatible = "socionext,uniphier-ld20-thermal";
-            interrupts = <0 3 1>;
-            #thermal-sensor-cells = <0>;
-        };
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    pvtctl: thermal-sensor {
+        compatible = "socionext,uniphier-ld20-thermal";
+        interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
+        #thermal-sensor-cells = <0>;
     };