ALSA: usx2y: Nuke pcm_list

It's nowhere actually used.

Link: https://lore.kernel.org/r/20210517131545.27252-12-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/usx2y/usbusx2y.h

@@ -46,7 +46,6 @@ struct usx2ydev {
 	struct snd_usx2y_substream	* volatile  prepare_subs;
 	wait_queue_head_t	prepare_wait_queue;
 	struct list_head	midi_list;
-	struct list_head	pcm_list;
 	int			pcm_devs;
 };
 

sound/usb/usx2y/usbusx2yaudio.c

@@ -1017,9 +1017,7 @@ static int usx2y_audio_stream_new(struct snd_card *card, int playback_endpoint,
  */
 int usx2y_audio_create(struct snd_card *card)
 {
-	int err = 0;
-
-	INIT_LIST_HEAD(&usx2y(card)->pcm_list);
+	int err;
 
 	err = usx2y_audio_stream_new(card, 0xA, 0x8);
 	if (err < 0)