dt-bindings: timer: Convert csky,gx6605s-timer to DT schema

Convert the C-SKY gx6605s timer binding to DT schema format. It's a
straight-forward conversion.

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

Documentation/devicetree/bindings/timer/csky,gx6605s-timer.txt

···
-=================
-gx6605s SOC Timer
-=================
-
-The timer is used in gx6605s soc as system timer and the driver
-contain clk event and clk source.
-
-==============================
-timer node bindings definition
-==============================
-
-	Description: Describes gx6605s SOC timer
-
-	PROPERTIES
-
-	- compatible
-		Usage: required
-		Value type: <string>
-		Definition: must be "csky,gx6605s-timer"
-	- reg
-		Usage: required
-		Value type: <u32 u32>
-		Definition: <phyaddr size> in soc from cpu view
-	- clocks
-		Usage: required
-		Value type: phandle + clock specifier cells
-		Definition: must be input clk node
-	- interrupt
-		Usage: required
-		Value type: <u32>
-		Definition: must be timer irq num defined by soc
-
-Examples:
----------
-
-	timer0: timer@20a000 {
-		compatible = "csky,gx6605s-timer";
-		reg = <0x0020a000 0x400>;
-		clocks = <&dummy_apb_clk>;
-		interrupts = <10>;
-		interrupt-parent = <&intc>;
-	};

Documentation/devicetree/bindings/timer/csky,gx6605s-timer.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/csky,gx6605s-timer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: gx6605s SOC Timer
+
+maintainers:
+  - Guo Ren <[e-mail]>
+
+properties:
+  compatible:
+    const: csky,gx6605s-timer
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    timer@20a000 {
+        compatible = "csky,gx6605s-timer";
+        reg = <0x0020a000 0x400>;
+        clocks = <&dummy_apb_clk>;
+        interrupts = <10>;
+    };