dt-bindings: watchdog: img,pdc-wdt: Convert to dtschema

Convert txt bindings of ImgTec's PDC watchdog timer to dtschema to allow
for validation.
Signed-off-by: Shresth Prasad <shrestprasad7@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240527195811.7897-2-shresthprasad7@gmail.comSigned-off-by: Rob Herring (Arm) <robh@kernel.org>

Documentation/devicetree/bindings/watchdog/img,pdc-wdt.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/watchdog/img,pdc-wdt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ImgTec PowerDown Controller (PDC) Watchdog Timer (WDT)
+
+maintainers:
+  - Shresth Prasad <shresthprasad7@gmail.com>
+
+allOf:
+  - $ref: watchdog.yaml#
+
+properties:
+  compatible:
+    enum:
+      - img,pdc-wdt
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: watchdog counter clock
+      - description: register interface clock
+
+  clock-names:
+    items:
+      - const: wdt
+      - const: sys
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    watchdog@18102100 {
+      compatible = "img,pdc-wdt";
+      reg = <0x18102100 0x100>;
+      clocks = <&pdc_wdt_clk>, <&sys_clk>;
+      clock-names = "wdt", "sys";
+      interrupts = <0 52 IRQ_TYPE_LEVEL_HIGH>;
+    };

Documentation/devicetree/bindings/watchdog/imgpdc-wdt.txt

-*ImgTec PowerDown Controller (PDC) Watchdog Timer (WDT)
-
-Required properties:
-- compatible : Should be "img,pdc-wdt"
-- reg : Should contain WDT registers location and length
-- clocks: Must contain an entry for each entry in clock-names.
-- clock-names: Should contain "wdt" and "sys"; the watchdog counter
-               clock and register interface clock respectively.
-- interrupts : Should contain WDT interrupt
-
-Examples:
-
-watchdog@18102100 {
-	compatible = "img,pdc-wdt";
-	reg = <0x18102100 0x100>;
-	clocks = <&pdc_wdt_clk>, <&sys_clk>;
-	clock-names = "wdt", "sys";
-	interrupts = <0 52 IRQ_TYPE_LEVEL_HIGH>;
-};