dt-bindings: watchdog: meson-gxbb-wdt: convert to yaml

Now that we have the DT validation in place, let's convert the device tree
bindings for the Amlogic GXBB Watchdog timer over to a YAML schemas.
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/watchdog/amlogic,meson-gxbb-wdt.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2019 BayLibre, SAS
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/watchdog/amlogic,meson-gxbb-wdt.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Meson GXBB SoCs Watchdog timer
+
+maintainers:
+  - Neil Armstrong <narmstrong@baylibre.com>
+
+properties:
+  compatible:
+    enum:
+      - amlogic,meson-gxbb-wdt
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+    description:
+      A phandle to the clock of this PHY
+
+required:
+  - compatible
+  - reg
+  - clocks
+
+examples:
+  - |
+    watchdog@98d0 {
+          compatible = "amlogic,meson-gxbb-wdt";
+          reg = <0x98d0 0x10>;
+          clocks = <&xtal>;
+    };

Documentation/devicetree/bindings/watchdog/meson-gxbb-wdt.txt

-Meson GXBB SoCs Watchdog timer
-
-Required properties:
-
-- compatible : should be "amlogic,meson-gxbb-wdt"
-- reg : Specifies base physical address and size of the registers.
-- clocks : Should be a phandle to the Watchdog clock source, for GXBB the xtal
-	   is the default clock source.
-
-Example:
-
-wdt: watchdog@98d0 {
-	compatible = "amlogic,meson-gxbb-wdt";
-	reg = <0 0x98d0 0x0 0x10>;
-	clocks = <&xtal>;
-};