ipvs: fix some sparse warnings

Add missing __percpu annotations and make ip_vs_net_id static.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
diff --git a/net/netfilter/ipvs/ip_vs_est.c b/net/netfilter/ipvs/ip_vs_est.c
index 0fac601..6bee6d0 100644
--- a/net/netfilter/ipvs/ip_vs_est.c
+++ b/net/netfilter/ipvs/ip_vs_est.c
@@ -56,7 +56,7 @@
  * Make a summary from each cpu
  */
 static void ip_vs_read_cpu_stats(struct ip_vs_stats_user *sum,
-				 struct ip_vs_cpu_stats *stats)
+				 struct ip_vs_cpu_stats __percpu *stats)
 {
 	int i;