ASoC: soc-core: add soc_rtd_free()

It is easy to read code if it is cleanly using paired function/naming,
like start <-> stop, register <-> unregister, etc, etc.
But, current ALSA SoC code is very random, unbalance, not paired, etc.
It is easy to create bug at the such code, and it will be difficult to
debug.

soc_rtd_init() was soc_post_component_init(), but there was no
its paired soc_post_component_free(), but it is done at
soc_remove_link_dais().
This means it is difficult to find related code.

This patch adds soc_rtd_free() which is paired soc_rtd_init().
soc_rtd_xxx() will be more cleanuped in the future.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87tva87lby.wl-kuninori.morimoto.gx@renesas.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-core.c

@@ -975,17 +975,15 @@ static void soc_remove_dai(struct snd_soc_dai *dai, int order)
 	dai->probed = 0;
 }
 
+static void soc_rtd_free(struct snd_soc_pcm_runtime *rtd); /* remove me */
 static void soc_remove_link_dais(struct snd_soc_card *card,
 		struct snd_soc_pcm_runtime *rtd, int order)
 {
 	int i;
 	struct snd_soc_dai *codec_dai;
 
-	/* unregister the rtd device */
-	if (rtd->dev_registered) {
-		device_unregister(rtd->dev);
-		rtd->dev_registered = 0;
-	}
+	/* finalize rtd device */
+	soc_rtd_free(rtd);
 
 	/* remove the CODEC DAI */
 	for_each_rtd_codec_dai(rtd, i, codec_dai)
@@ -1340,6 +1338,15 @@ static int soc_probe_component(struct snd_soc_card *card,
 	return ret;
 }
 
+static void soc_rtd_free(struct snd_soc_pcm_runtime *rtd)
+{
+	if (rtd->dev_registered) {
+		/* we don't need to call kfree() for rtd->dev */
+		device_unregister(rtd->dev);
+		rtd->dev_registered = 0;
+	}
+}
+
 static void soc_rtd_release(struct device *dev)
 {
 	kfree(dev);