ieee802154: constify struct net_device in some operations

Some of ieee802154 operations really shouldn't change passed net_device.
Constify passed argument.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>

drivers/ieee802154/fakehard.c

@@ -43,7 +43,7 @@ struct wpan_phy *net_to_phy(struct net_device *dev)
  *
  * Return the ID of the PAN from the PIB.
  */
-static u16 fake_get_pan_id(struct net_device *dev)
+static u16 fake_get_pan_id(const struct net_device *dev)
 {
 	BUG_ON(dev->type != ARPHRD_IEEE802154);
 
@@ -58,7 +58,7 @@ static u16 fake_get_pan_id(struct net_device *dev)
  * device. If the device has not yet had a short address assigned
  * then this should return 0xFFFF to indicate a lack of association.
  */
-static u16 fake_get_short_addr(struct net_device *dev)
+static u16 fake_get_short_addr(const struct net_device *dev)
 {
 	BUG_ON(dev->type != ARPHRD_IEEE802154);
 
@@ -78,7 +78,7 @@ static u16 fake_get_short_addr(struct net_device *dev)
  * Note: This is in section 7.2.1.2 of the IEEE 802.15.4-2006
  *       document.
  */
-static u8 fake_get_dsn(struct net_device *dev)
+static u8 fake_get_dsn(const struct net_device *dev)
 {
 	BUG_ON(dev->type != ARPHRD_IEEE802154);
 
@@ -98,7 +98,7 @@ static u8 fake_get_dsn(struct net_device *dev)
  * Note: This is in section 7.2.1.2 of the IEEE 802.15.4-2006
  *       document.
  */
-static u8 fake_get_bsn(struct net_device *dev)
+static u8 fake_get_bsn(const struct net_device *dev)
 {
 	BUG_ON(dev->type != ARPHRD_IEEE802154);
 

include/net/ieee802154_netdev.h

@@ -98,14 +98,14 @@ struct ieee802154_mlme_ops {
 	 * FIXME: these should become the part of PIB/MIB interface.
 	 * However we still don't have IB interface of any kind
 	 */
-	u16 (*get_pan_id)(struct net_device *dev);
-	u16 (*get_short_addr)(struct net_device *dev);
-	u8 (*get_dsn)(struct net_device *dev);
-	u8 (*get_bsn)(struct net_device *dev);
+	u16 (*get_pan_id)(const struct net_device *dev);
+	u16 (*get_short_addr)(const struct net_device *dev);
+	u8 (*get_dsn)(const struct net_device *dev);
+	u8 (*get_bsn)(const struct net_device *dev);
 };
 
 static inline struct ieee802154_mlme_ops *ieee802154_mlme_ops(
-		struct net_device *dev)
+		const struct net_device *dev)
 {
 	return dev->ml_priv;
 }