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>
diff --git a/include/net/wpan-phy.h b/include/net/wpan-phy.h
index a65e985..8592623 100644
--- a/include/net/wpan-phy.h
+++ b/include/net/wpan-phy.h
@@ -41,6 +41,10 @@
 	struct device dev;
 	int idx;
 
+	struct net_device *(*add_iface)(struct wpan_phy *phy,
+			const char *name);
+	void (*del_iface)(struct wpan_phy *phy, struct net_device *dev);
+
 	char priv[0] __attribute__((__aligned__(NETDEV_ALIGN)));
 };