ASoC: soc-core: add comment for for_each_xxx

soc-core has many for_each_xxx, but it is a little bit
difficult to know which list is relead to which for_each_xxx.
This patch adds missing comment for it.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87lfw5ahpj.wl-kuninori.morimoto.gx@renesas.comReviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-core.c

@@ -380,6 +380,7 @@ static void soc_free_pcm_runtime(struct snd_soc_pcm_runtime *rtd)
 static void soc_add_pcm_runtime(struct snd_soc_card *card,
 		struct snd_soc_pcm_runtime *rtd)
 {
+	/* see for_each_card_rtds */
 	list_add_tail(&rtd->list, &card->rtd_list);
 	rtd->num = card->num_rtd;
 	card->num_rtd++;
@@ -1149,6 +1150,7 @@ int snd_soc_add_dai_link(struct snd_soc_card *card,
 	if (dai_link->dobj.type && card->add_dai_link)
 		card->add_dai_link(card, dai_link);
 
+	/* see for_each_card_links */
 	list_add_tail(&dai_link->list, &card->dai_link_list);
 
 	return 0;