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

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>