dt-bindings: hwmon: add Microchip LAN966x bindings

Add a binding for the temperature sensor and the fan controller on the
Microchip LAN966x family.
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20220401214032.3738095-4-michael@walle.ccSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/microchip,lan966x.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/microchip,lan966x.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip LAN966x Hardware Monitor
+
+maintainers:
+  - Michael Walle <michael@walle.cc>
+
+description: |
+  Microchip LAN966x temperature monitor and fan controller
+
+properties:
+  compatible:
+    enum:
+      - microchip,lan9668-hwmon
+
+  reg:
+    items:
+      - description: PVT registers
+      - description: FAN registers
+
+  reg-names:
+    items:
+      - const: pvt
+      - const: fan
+
+  clocks:
+    maxItems: 1
+
+  '#thermal-sensor-cells':
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+
+additionalProperties: false
+
+examples:
+  - |
+    hwmon: hwmon@e2010180 {
+        compatible = "microchip,lan9668-hwmon";
+        reg = <0xe2010180 0xc>,
+              <0xe20042a8 0xc>;
+        reg-names = "pvt", "fan";
+        clocks = <&sys_clk>;
+        #thermal-sensor-cells = <0>;
+    };