ALSA: pcm: Fix referred substream in snd_pcm_action_group() unlock loop

In the unlock loop of snd_pcm_action_group(), the object "s" is used
as the check of nonatomic PCM, but it should be rather "s1", which is
the iterator of the loop.  This supposedly causes a kernel panic when
the substreams in operatino are linked.

Fixes: 257f8cce ('ALSA: pcm: Allow nonatomic trigger operations')
Reported-and-tested-by: Arthur Marsh <arthur.marsh@internode.on.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/pcm_native.c

@@ -818,7 +818,7 @@ static int snd_pcm_action_group(struct action_ops *ops,
 		/* unlock streams */
 		snd_pcm_group_for_each_entry(s1, substream) {
 			if (s1 != substream) {
-				if (s->pcm->nonatomic)
+				if (s1->pcm->nonatomic)
 					mutex_unlock(&s1->self_group.mutex);
 				else
 					spin_unlock(&s1->self_group.lock);