dt-bindings: pwm: convert lpc1850-sct-pwm.txt to yaml format

Convert lpc1850-sct-pwm.txt to yaml format.

Additional changes:
- add ref pwm.yaml.
- add resets property to match existed dts.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250616190435.1998078-1-Frank.Li@nxp.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

Documentation/devicetree/bindings/pwm/lpc1850-sct-pwm.txt

@@ -1,20 +0,0 @@
-* NXP LPC18xx State Configurable Timer - Pulse Width Modulator driver
-
-Required properties:
-  - compatible: Should be "nxp,lpc1850-sct-pwm"
-  - reg: Should contain physical base address and length of pwm registers.
-  - clocks: Must contain an entry for each entry in clock-names.
-    See ../clock/clock-bindings.txt for details.
-  - clock-names: Must include the following entries.
-    - pwm: PWM operating clock.
-  - #pwm-cells: Should be 3. See pwm.yaml in this directory for the description
-    of the cells format.
-
-Example:
-  pwm: pwm@40000000 {
-    compatible = "nxp,lpc1850-sct-pwm";
-    reg = <0x40000000 0x1000>;
-    clocks =<&ccu1 CLK_CPU_SCT>;
-    clock-names = "pwm";
-    #pwm-cells = <3>;
-  };

Documentation/devicetree/bindings/pwm/nxp,lpc1850-sct-pwm.yaml

@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/nxp,lpc1850-sct-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP LPC18xx State Configurable Timer
+
+maintainers:
+  - Frank Li <Frank.Li@nxp.com>
+
+properties:
+  compatible:
+    const: nxp,lpc1850-sct-pwm
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: pwm
+
+  '#pwm-cells':
+    const: 3
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - '#pwm-cells'
+
+allOf:
+  - $ref: pwm.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/lpc18xx-ccu.h>
+
+    pwm@40000000 {
+        compatible = "nxp,lpc1850-sct-pwm";
+        reg = <0x40000000 0x1000>;
+        clocks =<&ccu1 CLK_CPU_SCT>;
+        clock-names = "pwm";
+        #pwm-cells = <3>;
+    };