ASoC: add Renesas MSIOF sound driver

Merge series from Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>:

Renesas MSIOF can work as both SPI and I2S.
Current Linux supports MSIOF-SPI. This patch-set adds new MSIOF-I2S.

Because it is using same HW-IP, we want to share same compatible for both
MSIOF-SPI/I2S case. MSIOF-I2S (Sound) will use Audio-Graph-Card/Card2 which
uses Of-Graph, but  MSIOF-SPI is not use Of-Graph.
So, this patch-set assumes it was used as MSIOF-I2S if DT is using Of-Graph,
otherwise, it is MSIOF-SPI (This assumption will works if SPI *never*
use Of-Graph in the future).

One note so far is that it is using "spi@xxx" node name for both
MSIOF-SPI/I2S. DTC will automatically checks "spi@xxx" node as SPI device
which requests #address-cells/#size-cells. But is not needed for I2S.
So we will get warning about it on Sparrow Hawk which uses MSIOF-I2S.
We have no solution about it, so far.

Link: https://lore.kernel.org/r/87zfgi1a5a.wl-kuninori.morimoto.gx@renesas.com
Link: https://lore.kernel.org/r/87h62vh5mj.wl-kuninori.morimoto.gx@renesas.com
Link: https://lore.kernel.org/r/875xjeb0wu.wl-kuninori.morimoto.gx@renesas.com