ASoC: core: Fix obscure leak of runtime array

We're currently not freeing card->rtd in cases where the card is
unregistered before being instantiated - convert it to devm_kzalloc() to
make sure that happens.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>

sound/soc/soc-core.c

@@ -1686,7 +1686,6 @@ static int soc_cleanup_card_resources(struct snd_soc_card *card)
 
 	snd_soc_dapm_free(&card->dapm);
 
-	kfree(card->rtd);
 	snd_card_free(card->snd_card);
 	return 0;
 
@@ -3112,7 +3111,8 @@ int snd_soc_register_card(struct snd_soc_card *card)
 
 	soc_init_card_debugfs(card);
 
-	card->rtd = kzalloc(sizeof(struct snd_soc_pcm_runtime) *
+	card->rtd = devm_kzalloc(card->dev,
+				 sizeof(struct snd_soc_pcm_runtime) *
 				 (card->num_links + card->num_aux_devs),
 				 GFP_KERNEL);
 	if (card->rtd == NULL)