ALSA: line6: Remove superfluous out-of-memory error messages

Kernel already shows the error in the common path.

Tested-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/line6/playback.c

@@ -558,10 +558,8 @@ int line6_create_audio_out_urbs(struct snd_line6_pcm *line6pcm)
 		urb = line6pcm->urb_audio_out[i] =
 		    usb_alloc_urb(LINE6_ISO_PACKETS, GFP_KERNEL);
 
-		if (urb == NULL) {
-			dev_err(line6->ifcdev, "Out of memory\n");
+		if (urb == NULL)
 			return -ENOMEM;
-		}
 
 		urb->dev = line6->usbdev;
 		urb->pipe =