ASoC: imx-pcm-rpmsg: Multi-channel support for sound card based on rpmsg

Some sound card based on rpmsg may support multi-channel. The number of
channels can be sent to Cortex-M in rpmsg for process.

Signed-off-by: Chancel Liu <chancel.liu@nxp.com>
Acked-by: Shengjiu Wang <shengjiu.wang@gmail.com>
Link: https://lore.kernel.org/r/20220930064441.2548505-5-chancel.liu@nxp.com


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