net: constify remaining proto_ops

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dccp/ipv6.c

@@ -1158,7 +1158,7 @@ static const struct inet6_protocol dccp_v6_protocol = {
 	.flags		= INET6_PROTO_NOPOLICY | INET6_PROTO_FINAL,
 };
 
-static struct proto_ops inet6_dccp_ops = {
+static const struct proto_ops inet6_dccp_ops = {
 	.family		   = PF_INET6,
 	.owner		   = THIS_MODULE,
 	.release	   = inet6_release,