ipv6: sr: fix incorrect unregister order

Commit 5559cea ("ipv6: sr: fix possible use-after-free and
null-ptr-deref") changed the register order in seg6_init(). But the
unregister order in seg6_exit() is not updated.

Fixes: 5559cea ("ipv6: sr: fix possible use-after-free and null-ptr-deref")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240509131812.1662197-3-liuhangbin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: liuhangbin

net/ipv6/seg6.c

@@ -567,6 +567,6 @@ void seg6_exit(void)
 	seg6_local_exit();
 	seg6_iptunnel_exit();
 #endif
-	unregister_pernet_subsys(&ip6_segments_ops);
 	genl_unregister_family(&seg6_genl_family);
+	unregister_pernet_subsys(&ip6_segments_ops);
 }