ASoC: audio-graph-card2: recommend to use auto select DAI format

ASoC: audio-graph-card2: recommend to use auto select DAI format

"Simple Audio Card", "Audio Graph Card", "Audio Graph Card2" are
possible to set DAI format via DT.

OTOH, ASoC is supporting .auto_selectable_formats to select DAI
format automatically. Let's recommend to use it on "Audio Graph Card2".
One note is that it keeps supporting DAI format setting via DT.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://patch.msgid.link/87ik7s36k2.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>