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>
diff --git a/sound/usb/line6/midi.c b/sound/usb/line6/midi.c
index ebca5eb..f333cef 100644
--- a/sound/usb/line6/midi.c
+++ b/sound/usb/line6/midi.c
@@ -121,16 +121,13 @@
 
 	urb = usb_alloc_urb(0, GFP_ATOMIC);
 
-	if (urb == NULL) {
-		dev_err(line6->ifcdev, "Out of memory\n");
+	if (urb == NULL)
 		return -ENOMEM;
-	}
 
 	transfer_buffer = kmemdup(data, length, GFP_ATOMIC);
 
 	if (transfer_buffer == NULL) {
 		usb_free_urb(urb);
-		dev_err(line6->ifcdev, "Out of memory\n");
 		return -ENOMEM;
 	}