net/ipv6: Remove gc_link warn on in fib6_info_release

net/ipv6: Remove gc_link warn on in fib6_info_release

A revert of
   3dec89b14d37 ("net/ipv6: Remove expired routes with a separated list of routes")
was sent for net-next. Revert the remainder of 5a08d0065a915
which added a warn on if a fib entry is still on the gc_link list
to avoid compile failures when net is merged to net-next

Signed-off-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20231219030742.25715-1-dsahern@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>