[ALSA] Fix ASoC s3c24xx-pcm spinlock bug

This should fix a spinlock lockup bug on the s3c24xx arch.
From: Zoltan Devai <zdevai@gmail.com>

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

sound/soc/s3c24xx/s3c24xx-pcm.c

@@ -337,6 +337,8 @@ static int s3c24xx_pcm_open(struct snd_pcm_substream *substream)
 	if (prtd == NULL)
 		return -ENOMEM;
 
+	spin_lock_init(&prtd->lock);
+
 	runtime->private_data = prtd;
 	return 0;
 }