xfrm: input: constify xfrm_input_afinfo

Nothing writes to these structures (the module owner was not used).

While at it, size xfrm_input_afinfo[] by the highest existing xfrm family
(INET6), not AF_MAX.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

include/net/xfrm.h

@@ -349,13 +349,12 @@ struct xfrm_state_afinfo *xfrm_state_afinfo_get_rcu(unsigned int family);
 
 struct xfrm_input_afinfo {
 	unsigned int		family;
-	struct module		*owner;
 	int			(*callback)(struct sk_buff *skb, u8 protocol,
 					    int err);
 };
 
-int xfrm_input_register_afinfo(struct xfrm_input_afinfo *afinfo);
-int xfrm_input_unregister_afinfo(struct xfrm_input_afinfo *afinfo);
+int xfrm_input_register_afinfo(const struct xfrm_input_afinfo *afinfo);
+int xfrm_input_unregister_afinfo(const struct xfrm_input_afinfo *afinfo);
 
 void xfrm_state_delete_tunnel(struct xfrm_state *x);