dt-bindings: hwmon: Convert apm,xgene-slimpro-hwmon to DT schema

Convert APM X-Gene slimpro-hwmon binding to DT schema format. It's a
straight-forward conversion.

Signed-off-by: Rob Herring (Arm) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Guenter Roeck <[e-mail]>

Documentation/devicetree/bindings/hwmon/apm,xgene-slimpro-hwmon.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/apm,xgene-slimpro-hwmon.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: APM X-Gene SLIMpro hwmon
+
+maintainers:
+  - Khuong Dinh <[e-mail]>
+
+properties:
+  compatible:
+    const: apm,xgene-slimpro-hwmon
+
+  mboxes:
+    maxItems: 1
+
+required:
+  - compatible
+  - mboxes
+
+additionalProperties: false
+
+examples:
+  - |
+    hwmon {
+        compatible = "apm,xgene-slimpro-hwmon";
+        mboxes = <&mailbox 7>;
+    };

Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt

···
-APM X-Gene hwmon driver
-
-APM X-Gene SOC sensors are accessed over the "SLIMpro" mailbox.
-
-Required properties :
- - compatible : should be "apm,xgene-slimpro-hwmon"
- - mboxes : use the label reference for the mailbox as the first parameter.
-	    The second parameter is the channel number.
-
-Example :
-	hwmonslimpro {
-		compatible = "apm,xgene-slimpro-hwmon";
-		mboxes = <&mailbox 7>;
-	};