dt-bindings: thermal: Add DT bindings documentation for Amlogic Thermal

Adding the devicetree binding documentation for the Amlogic temperature
sensor found in the Amlogic Meson G12A and G12B SoCs.
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Tested-by: Christian Hewitt <christianshewitt@gmail.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Guillaume La Roque <glaroque@baylibre.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20191004090114.30694-2-glaroque@baylibre.com

Documentation/devicetree/bindings/thermal/amlogic,thermal.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/thermal/amlogic,thermal.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Amlogic Thermal
+
+maintainers:
+  - Guillaume La Roque <glaroque@baylibre.com>
+
+description: Binding for Amlogic Thermal
+
+properties:
+  compatible:
+      items:
+        - enum:
+            - amlogic,g12a-cpu-thermal
+            - amlogic,g12a-ddr-thermal
+        - const: amlogic,g12a-thermal
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  amlogic,ao-secure:
+    description: phandle to the ao-secure syscon
+    $ref: '/schemas/types.yaml#/definitions/phandle'
+
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - amlogic,ao-secure
+
+examples:
+  - |
+        cpu_temp: temperature-sensor@ff634800 {
+                compatible = "amlogic,g12a-cpu-thermal",
+                             "amlogic,g12a-thermal";
+                reg = <0xff634800 0x50>;
+                interrupts = <0x0 0x24 0x0>;
+                clocks = <&clk 164>;
+                #thermal-sensor-cells = <0>;
+                amlogic,ao-secure = <&sec_AO>;
+        };
+...