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>
diff --git a/net/ipv4/xfrm4_protocol.c b/net/ipv4/xfrm4_protocol.c
index dccefa9..8dd0e6ab 100644
--- a/net/ipv4/xfrm4_protocol.c
+++ b/net/ipv4/xfrm4_protocol.c
@@ -188,9 +188,8 @@ static const struct net_protocol ipcomp4_protocol = {
 	.netns_ok	=	1,
 };
 
-static struct xfrm_input_afinfo xfrm4_input_afinfo = {
+static const struct xfrm_input_afinfo xfrm4_input_afinfo = {
 	.family		=	AF_INET,
-	.owner		=	THIS_MODULE,
 	.callback	=	xfrm4_rcv_cb,
 };