drivers: net: xen-netback: use setup_timer() helper.

Use setup_timer function instead of initializing timer with the
    function and data fields.
Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/xen-netback/interface.c

@@ -520,8 +520,7 @@ int xenvif_init_queue(struct xenvif_queue *queue)
 
 	queue->credit_bytes = queue->remaining_credit = ~0UL;
 	queue->credit_usec  = 0UL;
-	init_timer(&queue->credit_timeout);
-	queue->credit_timeout.function = xenvif_tx_credit_callback;
+	setup_timer(&queue->credit_timeout, xenvif_tx_credit_callback, 0UL);
 	queue->credit_window_start = get_jiffies_64();
 
 	queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;