ALSA: usb-audio: Drop superfluous error message after disconnection

The error from snd_usb_lock_shutdown() indicates that the device is
disconnected, hence it makes no sense to show any further control
message error in get_ctl_value_v2().  Return the error directly
instead.
Tested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20211014130636.17860-3-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer.c

@@ -361,9 +361,8 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request,
 
 	memset(buf, 0, sizeof(buf));
 
-	ret = snd_usb_lock_shutdown(chip) ? -EIO : 0;
-	if (ret)
-		goto error;
+	if (snd_usb_lock_shutdown(chip))
+		return -EIO;
 
 	idx = mixer_ctrl_intf(cval->head.mixer) | (cval->head.id << 8);
 	ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0), bRequest,
@@ -372,7 +371,6 @@ static int get_ctl_value_v2(struct usb_mixer_elem_info *cval, int request,
 	snd_usb_unlock_shutdown(chip);
 
 	if (ret < 0) {
-error:
 		usb_audio_dbg(chip,
 			"cannot get ctl value: req = %#x, wValue = %#x, wIndex = %#x, type = %d\n",
 			request, validx, idx, cval->val_type);