ASoC: dt-bindings: ak4619: Add initial DT binding

Add Asahi Kasei ak4619 audio codec bindings.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://msgid.link/r/87h6dpwxug.wl-kuninori.morimoto.gx@renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/asahi-kasei,ak4619.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/asahi-kasei,ak4619.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: AK4619 I2C transmitter
+
+maintainers:
+  - Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
+  - Khanh Le <khanh.le.xr@renesas.com>
+
+allOf:
+  - $ref: dai-common.yaml#
+
+properties:
+  compatible:
+    const: asahi-kasei,ak4619
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: mclk
+
+  "#sound-dai-cells":
+    const: 0
+
+  port:
+    $ref: audio-graph-port.yaml#
+    unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        codec@10 {
+            compatible = "asahi-kasei,ak4619";
+            reg = <0x10>;
+
+            clocks = <&rcar_sound>;
+            clock-names = "mclk";
+
+            #sound-dai-cells = <0>;
+            port {
+                 ak4619_endpoint: endpoint {
+                       remote-endpoint = <&rsnd_endpoint>;
+                  };
+            };
+        };
+    };