ieee802154: add support for creation/removal of logic interfaces

Add support for two more NL802154 commands: ADD_IFACE and DEL_IFACE,
thus allowing creation and removal of logic WPAN interfaces on the top
of wpan-phy.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>

include/linux/nl802154.h

@@ -118,6 +118,8 @@ enum {
 
 	IEEE802154_LIST_IFACE,
 	IEEE802154_LIST_PHY,
+	IEEE802154_ADD_IFACE,
+	IEEE802154_DEL_IFACE,
 
 	__IEEE802154_CMD_MAX,
 };