ieee802154: add LIST_PHY command support

Add nl802154 command to get information about PHY's present in
the system.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
diff --git a/net/ieee802154/netlink.c b/net/ieee802154/netlink.c
index 5b738ec..8a22173 100644
--- a/net/ieee802154/netlink.c
+++ b/net/ieee802154/netlink.c
@@ -87,6 +87,10 @@
 	if (rc)
 		goto fail;
 
+	rc = nl802154_phy_register();
+	if (rc)
+		goto fail;
+
 	return 0;
 
 fail: