net/ipv4/ip_vti.c: Fix __rcu warnings detected by sparse.

With CONFIG_SPARSE_RCU_POINTER=y sparse identified references which did not
specificy __rcu in ip_vti.c
Signed-off-by: Saurabh Mohan <saurabh.mohan@vyatta.com>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_vti.c

@@ -55,7 +55,7 @@ struct vti_net {
 	struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
 	struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
 	struct ip_tunnel __rcu *tunnels_wc[1];
-	struct ip_tunnel **tunnels[4];
+	struct ip_tunnel __rcu **tunnels[4];
 
 	struct net_device *fb_tunnel_dev;
 };
@@ -160,7 +160,7 @@ static struct ip_tunnel *vti_tunnel_lookup(struct net *net,
 	return NULL;
 }
 
-static struct ip_tunnel **__vti_bucket(struct vti_net *ipn,
+static struct ip_tunnel __rcu **__vti_bucket(struct vti_net *ipn,
 					     struct ip_tunnel_parm *parms)
 {
 	__be32 remote = parms->iph.daddr;
@@ -179,7 +179,7 @@ static struct ip_tunnel **__vti_bucket(struct vti_net *ipn,
 	return &ipn->tunnels[prio][h];
 }
 
-static inline struct ip_tunnel **vti_bucket(struct vti_net *ipn,
+static inline struct ip_tunnel __rcu **vti_bucket(struct vti_net *ipn,
 						  struct ip_tunnel *t)
 {
 	return __vti_bucket(ipn, &t->parms);