l2: migrate old MULTIARCH macros to VLIB_NODE_FN

Change-Id: I8370c06150ce4499475e9d6dc6b3ab8be2016202
Signed-off-by: Filip Tehlar <ftehlar@cisco.com>
diff --git a/src/vnet/l2/l2_rw.h b/src/vnet/l2/l2_rw.h
index 49aa25f..f9b1033 100644
--- a/src/vnet/l2/l2_rw.h
+++ b/src/vnet/l2/l2_rw.h
@@ -84,6 +84,8 @@
 int l2_rw_mod_entry (u32 * index,
 		     u8 * mask, u8 * value, u32 len, u32 skip, u8 is_del);
 
+extern vlib_node_registration_t l2_rw_node;
+
 #endif /* L2_FW_H_ */
 
 /*