dt-bindings: soc: bcm: document brcm,bcm2711-avs-monitor

Document alreasdy used binding for Syscon / AVS monitor:
brcm,bcm2711-avs-monitor to fix dt_binding_check and dtbs_check warnings
like:

  brcm,avs-ro-thermal.example.dtb: /example-0/avs-monitor@7d5d2000: failed to match any schema with compatible: ['brcm,bcm2711-avs-monitor', 'syscon', 'simple-mfd']

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20240517125138.53441-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>

Documentation/devicetree/bindings/soc/bcm/brcm,bcm2711-avs-monitor.yaml

@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/bcm/brcm,bcm2711-avs-monitor.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom AVS Monitor
+
+maintainers:
+  - Stefan Wahren <wahrenst@gmx.net>
+
+properties:
+  compatible:
+    items:
+      - const: brcm,bcm2711-avs-monitor
+      - const: syscon
+      - const: simple-mfd
+
+  reg:
+    maxItems: 1
+
+  thermal:
+    $ref: /schemas/thermal/brcm,avs-ro-thermal.yaml
+    description: Broadcom AVS ring oscillator thermal
+
+required:
+  - compatible
+  - reg
+  - thermal
+
+additionalProperties: false
+
+examples:
+  - |
+    avs-monitor@7d5d2000 {
+        compatible = "brcm,bcm2711-avs-monitor", "syscon", "simple-mfd";
+        reg = <0x7d5d2000 0xf00>;
+
+        thermal: thermal {
+            compatible = "brcm,bcm2711-thermal";
+            #thermal-sensor-cells = <0>;
+        };
+    };
+...