ipvs: Reject ipv6 link-local addresses for destinations

We can't use non-local link-local addresses for destinations, without
knowing the interface on which we can reach the address. Reject them for
now.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>