face: move common declarations to face-common.hpp

Change-Id: I0e3e7a93f0693b0e24ca67493a4229987e792ef4
diff --git a/daemon/face/ethernet-channel.cpp b/daemon/face/ethernet-channel.cpp
index 9c27ada..0104b19 100644
--- a/daemon/face/ethernet-channel.cpp
+++ b/daemon/face/ethernet-channel.cpp
@@ -25,6 +25,7 @@
 
 #include "ethernet-channel.hpp"
 #include "ethernet-protocol.hpp"
+#include "face.hpp"
 #include "generic-link-service.hpp"
 #include "unicast-ethernet-transport.hpp"
 #include "common/global.hpp"