ipvs: add more mcast parameters for the sync daemon

- mcast_group: configure the multicast address, now IPv6
is supported too

- mcast_port: configure the multicast port

- mcast_ttl: configure the multicast TTL/HOP_LIMIT

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>