ASoC: Add ak4619 codec support

Add support for the Asahi Kasei AK4619 audio codec.

[Kuninori cleanuped and adjusted to upstream code]

Signed-off-by: Khanh Le <khanh.le.xr@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://msgid.link/r/87iky5wxvr.wl-kuninori.morimoto.gx@renesas.com


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