dt-bindings: timer: Convert stm32 timer bindings to json-schema

Convert the STM32 timer binding to DT schema format using json-schema
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/timer/st,stm32-timer.txt

-. STMicroelectronics STM32 timer
-
-The STM32 MCUs family has several general-purpose 16 and 32 bits timers.
-
-Required properties:
-- compatible : Should be "st,stm32-timer"
-- reg : Address and length of the register set
-- clocks : Reference on the timer input clock
-- interrupts : Reference to the timer interrupt
-
-Optional properties:
-- resets: Reference to a reset controller asserting the timer
-
-Example:
-
-timer5: timer@40000c00 {
-	compatible = "st,stm32-timer";
-	reg = <0x40000c00 0x400>;
-	interrupts = <50>;
-	resets = <&rrc 259>;
-	clocks = <&clk_pmtr1>;
-};

Documentation/devicetree/bindings/timer/st,stm32-timer.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/st,stm32-timer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics STM32 general-purpose 16 and 32 bits timers bindings
+
+maintainers:
+  - Benjamin Gaignard <benjamin.gaignard@st.com>
+
+properties:
+  compatible:
+    const: st,stm32-timer
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/stm32mp1-clks.h>
+    timer: timer@40000c00 {
+        compatible = "st,stm32-timer";
+        reg = <0x40000c00 0x400>;
+        interrupts = <50>;
+        clocks = <&clk_pmtr1>;
+    };
+
+...