netfilter: ipvs: fix compiler warnings

Fix compiler warnings when no transport protocol load balancing support
is configured.

[horms@verge.net.au: removed suprious __ip_vs_cleanup() clean-up hunk]
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Simon Horman <horms@verge.net.au>