mac802154: sparse warnings: make symbols static

Make symbols static to avoid the following warning shown up
by sparse:

    warning: symbol ... was not declared. Should it be static?
Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mac802154/mac_cmd.c

@@ -55,7 +55,7 @@ static int mac802154_mlme_start_req(struct net_device *dev,
 	return 0;
 }
 
-struct wpan_phy *mac802154_get_phy(const struct net_device *dev)
+static struct wpan_phy *mac802154_get_phy(const struct net_device *dev)
 {
 	struct mac802154_sub_if_data *priv = netdev_priv(dev);
 

net/mac802154/mib.c

@@ -39,7 +39,7 @@ struct hw_addr_filt_notify_work {
 	unsigned long changed;
 };
 
-struct mac802154_priv *mac802154_slave_get_priv(struct net_device *dev)
+static struct mac802154_priv *mac802154_slave_get_priv(struct net_device *dev)
 {
 	struct mac802154_sub_if_data *priv = netdev_priv(dev);