ASoC: Add ak4619 codec support

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

This is v3 patch-set for ak4619 driver.
It was created by Khanh, and I updated/adjusted to upstream.
It was tested on Renesas V4M GrayH

Link: https://lore.kernel.org/r/877ceotnrg.wl-kuninori.morimoto.gx@renesas.com
Link: https://lore.kernel.org/r/87frtb3x4k.wl-kuninori.morimoto.gx@renesas.com