ethernet :mellanox :mlx4: Replace pci_pool_alloc by pci_pool_zalloc

In mlx4_alloc_cmd_mailbox(), pci_pool_alloc() followed by memset will be
replaced by pci_pool_zalloc()
Signed-off-by: Souptick joarder <jrdr.linux@gmail.com>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/cmd.c

@@ -2679,15 +2679,13 @@ struct mlx4_cmd_mailbox *mlx4_alloc_cmd_mailbox(struct mlx4_dev *dev)
 	if (!mailbox)
 		return ERR_PTR(-ENOMEM);
 
-	mailbox->buf = pci_pool_alloc(mlx4_priv(dev)->cmd.pool, GFP_KERNEL,
+	mailbox->buf = pci_pool_zalloc(mlx4_priv(dev)->cmd.pool, GFP_KERNEL,
 				       &mailbox->dma);
 	if (!mailbox->buf) {
 		kfree(mailbox);
 		return ERR_PTR(-ENOMEM);
 	}
 
-	memset(mailbox->buf, 0, MLX4_MAILBOX_SIZE);
-
 	return mailbox;
 }
 EXPORT_SYMBOL_GPL(mlx4_alloc_cmd_mailbox);