vhost: make interval tree static inline

vhost_umem_interval_tree is only used locally within vhost.c, mark it
static. As some functions generated go unused, this triggers warnings
unless we also mark it inline.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vhost/vhost.c

@@ -49,7 +49,7 @@ enum {
 
 INTERVAL_TREE_DEFINE(struct vhost_umem_node,
 		     rb, __u64, __subtree_last,
-		     START, LAST, , vhost_umem_interval_tree);
+		     START, LAST, static inline, vhost_umem_interval_tree);
 
 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)