tcp: make nla_policy const

Signed-off-by: NStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp_metrics.c

@@ -751,7 +751,7 @@ static struct genl_family tcp_metrics_nl_family = {
 	.netnsok	= true,
 };
 
-static struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = {
+static const struct nla_policy tcp_metrics_nl_policy[TCP_METRICS_ATTR_MAX + 1] = {
 	[TCP_METRICS_ATTR_ADDR_IPV4]	= { .type = NLA_U32, },
 	[TCP_METRICS_ATTR_ADDR_IPV6]	= { .type = NLA_BINARY,
 					    .len = sizeof(struct in6_addr), },