staging: rtl8192u: r8192U_core: don't print error when allocating urb fails

kmalloc will print enough information in case of failure.
Signed-off-by: Wolfram Sang <wsa-dev@sang-engineering.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/r8192U_core.c

@@ -1702,11 +1702,8 @@ short rtl8192_tx(struct net_device *dev, struct sk_buff *skb)
 		}
 		if (bSend0Byte) {
 			tx_urb_zero = usb_alloc_urb(0, GFP_ATOMIC);
-			if (!tx_urb_zero) {
-				RT_TRACE(COMP_ERR,
-					 "can't alloc urb for zero byte\n");
+			if (!tx_urb_zero)
 				return -ENOMEM;
-			}
 			usb_fill_bulk_urb(tx_urb_zero, udev,
 					  usb_sndbulkpipe(udev, idx_pipe),
 					  &zero, 0, tx_zero_isr, dev);