net/sched: avoid unused-label warning

The label is only used from inside the #ifdef and should be
hidden the same way, to avoid this warning:

net/sched/act_tunnel_key.c: In function 'tunnel_key_init':
net/sched/act_tunnel_key.c:389:1: error: label 'release_tun_meta' defined but not used [-Werror=unused-label]
release_tun_meta:

Fixes: 41411e2fd6b8 ("net/sched: act_tunnel_key: Add dst_cache support")
Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/sched/act_tunnel_key.c

···
 #ifdef CONFIG_DST_CACHE
 	if (metadata)
 		dst_cache_destroy(&metadata->u.tun_info.dst_cache);
-#endif
 release_tun_meta:
+#endif
 	if (metadata)
 		dst_release(&metadata->dst);