ASoC: simple-card-utils: use for_each_prop_xxx()

ASoC is now supporting multi DAI, but, current
simple-card / audio-graph are assuming fixed single DAI.

This patch uses for_each_prop_xxx() to support multi DAI.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87r1jgwf9y.wl-kuninori.morimoto.gx@renesas.com


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