dt-bindings: pwm: Convert imx tpm pwm to json-schema

Convert the imx tpm pwm binding to DT schema format using json-schema.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/pwm/imx-tpm-pwm.txt

-Freescale i.MX TPM PWM controller
-
-Required properties:
-- compatible : Should be "fsl,imx7ulp-pwm".
-- reg: Physical base address and length of the controller's registers.
-- #pwm-cells: Should be 3. See pwm.yaml in this directory for a description of the cells format.
-- clocks : The clock provided by the SoC to drive the PWM.
-- interrupts: The interrupt for the PWM controller.
-
-Note: The TPM counter and period counter are shared between multiple channels, so all channels
-should use same period setting.
-
-Example:
-
-tpm4: pwm@40250000 {
-	compatible = "fsl,imx7ulp-pwm";
-	reg = <0x40250000 0x1000>;
-	assigned-clocks = <&pcc2 IMX7ULP_CLK_LPTPM4>;
-	assigned-clock-parents = <&scg1 IMX7ULP_CLK_SOSC_BUS_CLK>;
-	clocks = <&pcc2 IMX7ULP_CLK_LPTPM4>;
-	#pwm-cells = <3>;
-};

Documentation/devicetree/bindings/pwm/imx-tpm-pwm.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/imx-tpm-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale i.MX TPM PWM controller
+
+maintainers:
+  - Anson Huang <anson.huang@nxp.com>
+
+description: |
+  The TPM counter and period counter are shared between multiple
+  channels, so all channels should use same period setting.
+
+properties:
+  "#pwm-cells":
+    const: 3
+
+  compatible:
+    enum:
+      - fsl,imx7ulp-pwm
+
+  reg:
+    maxItems: 1
+
+  assigned-clocks:
+    maxItems: 1
+
+  assigned-clock-parents:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+required:
+  - "#pwm-cells"
+  - compatible
+  - reg
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/imx7ulp-clock.h>
+
+    pwm@40250000 {
+        compatible = "fsl,imx7ulp-pwm";
+        reg = <0x40250000 0x1000>;
+        assigned-clocks = <&pcc2 IMX7ULP_CLK_LPTPM4>;
+        assigned-clock-parents = <&scg1 IMX7ULP_CLK_SOSC_BUS_CLK>;
+        clocks = <&pcc2 IMX7ULP_CLK_LPTPM4>;
+        #pwm-cells = <3>;
+    };