ASoC: Add support for Loongson I2S controller

Loongson I2S controller is found on 7axxx/2kxxx chips from loongson,
it is a PCI device with two private DMA controllers, one for playback,
the other for capture.

The driver supports the use of DTS or ACPI to describe device resources.

Signed-off-by: Yingkun Meng <mengyingkun@loongson.cn>
Link: https://lore.kernel.org/r/20230615122718.3412942-1-mengyingkun@loongson.cn


Signed-off-by: Mark Brown <broonie@kernel.org>