ASoC: audio-graph-scu-card: care multi DPCM codec_conf

Current audio-graph-scu-card didn't care about codec_conf
for multi DPCM case. This patch cares it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>