decnet: Move rtm_dn_policy to dn_route to make it available if !CONFIG_DECNET_ROUTER

Otherwise build fails with CONFIG_DECNET && !CONFIG_DECNET_ROUTER

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 5904429..fe32388 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -1613,6 +1613,20 @@
 	return -EMSGSIZE;
 }
 
+const struct nla_policy rtm_dn_policy[RTA_MAX + 1] = {
+	[RTA_DST]		= { .type = NLA_U16 },
+	[RTA_SRC]		= { .type = NLA_U16 },
+	[RTA_IIF]		= { .type = NLA_U32 },
+	[RTA_OIF]		= { .type = NLA_U32 },
+	[RTA_GATEWAY]		= { .type = NLA_U16 },
+	[RTA_PRIORITY]		= { .type = NLA_U32 },
+	[RTA_PREFSRC]		= { .type = NLA_U16 },
+	[RTA_METRICS]		= { .type = NLA_NESTED },
+	[RTA_MULTIPATH]		= { .type = NLA_NESTED },
+	[RTA_TABLE]		= { .type = NLA_U32 },
+	[RTA_MARK]		= { .type = NLA_U32 },
+};
+
 /*
  * This is called by both endnodes and routers now.
  */