farsync: fix info leak in ioctl

The fst_get_iface() 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: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
fst_enable_intr(struct fst_card_info *card)
{
	if (card->family == FST_FAMILY_TXU) {
		outl(0x0f0c0900, card->pci_conf + INTCSR_9054);
	} else {
		outw(0x0543, card->pci_conf + INTCSR_9052);
	}
}

fst_enable_intr(struct fst_card_info *card)
{
	if (card->family == FST_FAMILY_TXU) {
		outl(0x0f0c0900, card->pci_conf + INTCSR_9054);
	} else {
		outw(0x0543, card->pci_conf + INTCSR_9052);
	}
}
