Support to use lg2 logging

Change-Id: I3a11433fa6bbbad165a65037b9253eda7206f946
diff --git a/util/trace.hpp b/util/trace.hpp
index ef940fd..ccafd98 100644
--- a/util/trace.hpp
+++ b/util/trace.hpp
@@ -3,6 +3,8 @@
 #include <inttypes.h>
 #include <stdio.h>
 
+#include <phosphor-logging/lg2.hpp>
+
 #include <cstdarg>
 
 #ifndef TEST_TRACE