ALSA: usb-audio: Check shutdown at endpoint_set_interface()

The call of usb_set_interface() and a delay are superfluous when the
device has been already disconnected.  Add a disconnection check
before doing it.

Link: https://patch.msgid.link/20240808091522.31415-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/endpoint.c

@@ -921,6 +921,9 @@ static int endpoint_set_interface(struct snd_usb_audio *chip,
 
 	if (ep->iface_ref->altset == altset)
 		return 0;
+	/* already disconnected? */
+	if (unlikely(atomic_read(&chip->shutdown)))
+		return -ENODEV;
 
 	usb_audio_dbg(chip, "Setting usb interface %d:%d for EP 0x%x\n",
 		      ep->iface, altset, ep->ep_num);