ASoC: fsl_rpmsg: Add CPU DAI driver for audio base on rpmsg

This is a cpu dai driver for rpmsg audio use case,
which is mainly used for getting the user's configuration
from devicetree and configure the clocks which is used by
Cortex-M core.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1615516725-4975-3-git-send-email-shengjiu.wang@nxp.com


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