ASoC: simple-card-utils: indicate dai_fmt if exist

link->dai_fmt might be 0.
Don't indicate it in such case when debugging.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87mtu4wf9k.wl-kuninori.morimoto.gx@renesas.com


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