dt-bindings: arm: airoha: Add the chip-scu node for EN7581 SoC

This patch adds the chip-scu document bindings for EN7581 SoC.
The airoha chip-scu block provides a configuration interface for clock,
io-muxing and other functionalities used by multiple controllers (e.g.
clock, pinctrl, ecc.) on EN7581 SoC.

Reviewed-by: Rob Herring (Arm) <[e-mail]>
Reviewed-by: AngeloGioacchino Del Regno <[e-mail]>
Signed-off-by: Lorenzo Bianconi <[e-mail]>
Link: https://lore.kernel.org/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

Documentation/devicetree/bindings/arm/airoha,en7581-chip-scu.yaml

···
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/airoha,en7581-chip-scu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Airoha Chip SCU Controller for EN7581 SoC
+
+maintainers:
+  - Lorenzo Bianconi <[e-mail]>
+
+description:
+  The airoha chip-scu block provides a configuration interface for clock,
+  io-muxing and other functionalities used by multiple controllers (e.g. clock,
+  pinctrl, ecc) on EN7581 SoC.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - airoha,en7581-chip-scu
+      - const: syscon
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+      #address-cells = <2>;
+      #size-cells = <2>;
+      syscon@1fa20000 {
+        compatible = "airoha,en7581-chip-scu", "syscon";
+        reg = <0x0 0x1fa20000 0x0 0x388>;
+      };
+    };