ASoc: dt-bindings: PCM6240: Add initial DT binding

ASoc: dt-bindings: PCM6240: Add initial DT binding

PCM6240 family chips are popular among audio customers, in spite of only a
portion of the functionality of codec, such as ADC or DAC, and so on, for
different Specifications, range from Personal Electric to Automotive
Electric, even some professional fields. Yet their audio performance is far
superior to the codec's, and cost is lower than codec, and much easier to
program than codec.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Shenghao Ding <shenghao-ding@ti.com>
Link: https://lore.kernel.org/r/20240407091846.1299-5-shenghao-ding@ti.com
Signed-off-by: Mark Brown <broonie@kernel.org>