wanxl: fix info leak in ioctl

The wanxl_ioctl() code fails to initialize the two padding bytes of
struct sync_serial_settings after the ->loopback member. Add an explicit
memset(0) before filling the structure to avoid the info leak.

Signed-off-by: Salva Peiró <speiro@ai2.upv.es>
Signed-off-by: David S. Miller <davem@davemloft.net>
static int __init wanxl_init_module(void)
{
#ifdef MODULE
	pr_info("%s\n", version);
#endif
	return pci_register_driver(&wanxl_pci_driver);
}

static int __init wanxl_init_module(void)
{
#ifdef MODULE
	pr_info("%s\n", version);
#endif
	return pci_register_driver(&wanxl_pci_driver);
}
