ALSA: hda/hdmi: Fix incorrect mutex unlock in silent_stream_disable()

The silent_stream_disable() function introduced by the commit
b1a50397 ("ALSA: hda/hdmi: fix silent stream for first playback to
DP") takes the per_pin->lock mutex, but it unlocks the wrong one,
spec->pcm_lock, which causes a deadlock.  This patch corrects it.

Fixes: b1a50397 ("ALSA: hda/hdmi: fix silent stream for first playback to DP")
Reported-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Cc: <stable@vger.kernel.org>
Acked-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20210101083852.12094-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_hdmi.c

@@ -1733,7 +1733,7 @@ static void silent_stream_disable(struct hda_codec *codec,
 	per_pin->silent_stream = false;
 
  unlock_out:
-	mutex_unlock(&spec->pcm_lock);
+	mutex_unlock(&per_pin->lock);
 }
 
 /* update ELD and jack state via audio component */