net: fib_rules: mark arguments to fib_rules_register const and __net_initdata

fib_rules_register() duplicates the template passed to it without modification,
mark the argument as const. Additionally the templates are only needed when
instantiating a new namespace, so mark them as __net_initdata, which means
they can be discarded when CONFIG_NET_NS=n.

Signed-off-by: Patrick McHardy <kaber@trash.net>
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index a2df501..7d3e382a 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -216,7 +216,7 @@
 	return 0;
 }
 
-static struct fib_rules_ops ipmr_rules_ops_template = {
+static const struct fib_rules_ops __net_initdata ipmr_rules_ops_template = {
 	.family		= FIB_RULES_IPMR,
 	.rule_size	= sizeof(struct ipmr_rule),
 	.addr_size	= sizeof(u32),