ASoC: dt-bindings: Convert mxs-saif.txt to fsl,saif.yaml (imx28 saif)

The 'fsl,imx28-saif' compatible has already the mxs-saif.txt description.
This patch converts (and removes it) this file to fsl,saif.yaml (to follow
current fsl convention).

Changes for the mxs-saif.txt:
- Adds 'clocks', '#clock-cells' and '#sound-dai-cells' properties
- Provide device description

Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20240828092709.2626359-1-lukma@denx.de
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/sound/fsl,saif.yaml

@@ -0,0 +1,83 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/sound/fsl,saif.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale MXS Serial Audio Interface (SAIF)
+
+maintainers:
+  - Lukasz Majewski <lukma@denx.de>
+
+allOf:
+  - $ref: dai-common.yaml#
+
+description:
+  The SAIF is based on I2S module that is used to communicate with audio codecs,
+  but only with half-duplex manner (i.e. it can either transmit or receive PCM
+  audio).
+
+properties:
+  compatible:
+    const: fsl,imx28-saif
+
+  reg:
+    maxItems: 1
+
+  "#sound-dai-cells":
+    const: 0
+
+  interrupts:
+    maxItems: 1
+
+  dmas:
+    maxItems: 1
+
+  dma-names:
+    const: rx-tx
+
+  "#clock-cells":
+    description: Configure the I2S device as MCLK clock provider.
+    const: 0
+
+  clocks:
+    maxItems: 1
+
+  fsl,saif-master:
+    description: Indicate that saif is a slave and its phandle points to master
+    $ref: /schemas/types.yaml#/definitions/phandle
+
+required:
+  - compatible
+  - reg
+  - "#sound-dai-cells"
+  - interrupts
+  - dmas
+  - dma-names
+  - clocks
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    saif0: saif@80042000 {
+        compatible = "fsl,imx28-saif";
+        reg = <0x80042000 2000>;
+        #sound-dai-cells = <0>;
+        interrupts = <59>;
+        dmas = <&dma_apbx 4>;
+        dma-names = "rx-tx";
+        #clock-cells = <0>;
+        clocks = <&clks 53>;
+    };
+  - |
+    saif1: saif@80046000 {
+        compatible = "fsl,imx28-saif";
+        reg = <0x80046000 2000>;
+        #sound-dai-cells = <0>;
+        interrupts = <58>;
+        dmas = <&dma_apbx 5>;
+        dma-names = "rx-tx";
+        clocks = <&clks 53>;
+        fsl,saif-master = <&saif0>;
+    };