ASoC: soc-dai: move snd_soc_dai_stream_valid() to soc-dai.c

snd_soc_dai_stream_valid() is function to check stream validity.
But, some code is using it, some code are checking stream->channels_min
directly. Doing samethings by different method is confusable.
This patch uses same funcntion for same purpose.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87ftmyhmzz.wl-kuninori.morimoto.gx@renesas.com


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