ASoC: dt-bindings: fsl-asoc-card: Document fsl,imx25-pdk-sgtl5000

ASoC: dt-bindings: fsl-asoc-card: Document fsl,imx25-pdk-sgtl5000

Document fsl,imx25-pdk-sgtl5000 to fix the following dt-schema warning:

imx25-pdk.dtb: sound: compatible: 'oneOf' conditional failed, one must be fixed:
	['fsl,imx25-pdk-sgtl5000', 'fsl,imx-audio-sgtl5000'] is too long

Fixes: 4189b54220e5 ("ASoC: dt-bindings: fsl-asoc-card: convert to YAML")
Signed-off-by: Fabio Estevam <festevam@denx.de>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20240412121410.2948048-1-festevam@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>