nl802154: make ieee802154_policy constant

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/nl802154.h b/include/linux/nl802154.h
index 2cda00c..266dd96 100644
--- a/include/linux/nl802154.h
+++ b/include/linux/nl802154.h
@@ -69,7 +69,7 @@
 
 #define IEEE802154_ATTR_MAX (__IEEE802154_ATTR_MAX - 1)
 
-extern struct nla_policy ieee802154_policy[];
+extern const struct nla_policy ieee802154_policy[];
 
 /* commands */
 /* REQ should be responded with CONF