fou: make nla_policy const

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index 321d57f..cf50f7e 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -631,7 +631,7 @@
 	.netnsok	= true,
 };
 
-static struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
+static const struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
 	[FOU_ATTR_PORT] = { .type = NLA_U16, },
 	[FOU_ATTR_AF] = { .type = NLA_U8, },
 	[FOU_ATTR_IPPROTO] = { .type = NLA_U8, },