ASoC: fsl_easrc: Add EASRC ASoC CPU DAI drivers

EASRC (Enhanced Asynchronous Sample Rate Converter) is a new IP module
found on i.MX8MN. It is different with old ASRC module.

The primary features for the EASRC are as follows:
- 4 Contexts - groups of channels with an independent time base
- Fully independent and concurrent context control
- Simultaneous processing of up to 32 audio channels
- Programmable filter charachteristics for each context
- 32, 24, 20, and 16-bit fixed point audio sample support
- 32-bit floating point audio sample support
- 8kHz to 384kHz sample rate
- 1/16 to 8x sample rate conversion ratio

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Signed-off-by: Cosmin-Gabriel Samoila <cosmin.samoila@nxp.com>
Acked-by: Nicolin Chen <nicoleotsuka@gmail.com>
Link: https://lore.kernel.org/r/260d7a9fbddf9fa90760d30095df60a4c25fd0a1.1587038908.git.shengjiu.wang@nxp.com


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