dt-bindings: timer: Convert arm,mps2-timer to DT schema

Convert the Arm MPS2 Timer binding to DT schema format. It's a
straight-forward conversion.

Signed-off-by: Rob Herring (Arm) <[e-mail]>
Reviewed-by: Liviu Dudau <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Daniel Lezcano <[e-mail]>

Documentation/devicetree/bindings/timer/arm,mps2-timer.txt

···
-ARM MPS2 timer
-
-The MPS2 platform has simple general-purpose 32 bits timers.
-
-Required properties:
-- compatible	: Should be "arm,mps2-timer"
-- reg		: Address and length of the register set
-- interrupts	: Reference to the timer interrupt
-
-Required clocking property, have to be one of:
-- clocks	  : The input clock of the timer
-- clock-frequency : The rate in HZ in input of the ARM MPS2 timer
-
-Examples:
-
-timer1: mps2-timer@40000000 {
-	compatible = "arm,mps2-timer";
-	reg = <0x40000000 0x1000>;
-	interrupts = <8>;
-	clocks = <&sysclk>;
-};
-
-timer2: mps2-timer@40001000 {
-	compatible = "arm,mps2-timer";
-	reg = <0x40001000 0x1000>;
-	interrupts = <9>;
-	clock-frequency = <25000000>;
-};

Documentation/devicetree/bindings/timer/arm,mps2-timer.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm,mps2-timer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARM MPS2 timer
+
+maintainers:
+  - Vladimir Murzin <[e-mail]>
+
+description:
+  The MPS2 platform has simple general-purpose 32 bits timers.
+
+properties:
+  compatible:
+    const: arm,mps2-timer
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-frequency:
+    description: Rate in Hz of the timer input clock
+
+oneOf:
+  - required: [clocks]
+  - required: [clock-frequency]
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    timer@40000000 {
+        compatible = "arm,mps2-timer";
+        reg = <0x40000000 0x1000>;
+        interrupts = <8>;
+        clocks = <&sysclk>;
+    };