ASoC: soc-core: skip zero num_dai component in searching dai name

In the case like dmaengine which's not a dai but as a component, the
num_dai is zero, dmaengine component has the same component_of_node
as cpu dai, when cpu dai component is not ready, but dmaengine component
is ready, try to get cpu dai name, the snd_soc_get_dai_name() return
-EINVAL, not -EPROBE_DEFER, that cause below error:

asoc-simple-card <card name>: parse error -22
asoc-simple-card: probe of <card name> failed with error -22

The sound card failed to probe.

So this patch fixes the issue above by skipping the zero num_dai
component in searching dai name.

Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Link: https://lore.kernel.org/r/1644491952-7457-1-git-send-email-shengjiu.wang@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>