[NETLINK]: Mark netlink policies const

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 329de67..5a5f8bd 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2990,7 +2990,7 @@
 	return pfx;
 }
 
-static struct nla_policy ifa_ipv6_policy[IFA_MAX+1] __read_mostly = {
+static const struct nla_policy ifa_ipv6_policy[IFA_MAX+1] = {
 	[IFA_ADDRESS]		= { .len = sizeof(struct in6_addr) },
 	[IFA_LOCAL]		= { .len = sizeof(struct in6_addr) },
 	[IFA_CACHEINFO]		= { .len = sizeof(struct ifa_cacheinfo) },