Add default time sync object path

The time sync object path is empty by default and is initialized by a
dbus call at runtime.
It works OK in BMC but the unit tests in the repo is broken due to the
empty string used in the sdbus matcht_t.

Add a config option to initialize the default time sync object path, so
that it works both on BMC and in unit tests.

Signed-off-by: Lei YU <yulei.sh@bytedance.com>
Change-Id: Iccdaef58434a1227c4ea73230ba23b4e618a2d2d
diff --git a/settings.hpp b/settings.hpp
index b7e18bf..a61cae7 100644
--- a/settings.hpp
+++ b/settings.hpp
@@ -1,5 +1,7 @@
 #pragma once
 
+#include "config.h"
+
 #include "utils.hpp"
 
 #include <sdbusplus/bus.hpp>
@@ -33,7 +35,7 @@
     ~Objects() = default;
 
     /** @brief time sync method settings object */
-    Path timeSyncMethod;
+    Path timeSyncMethod = DEFAULT_TIME_SYNC_OBJECT_PATH;
 };
 
 } // namespace settings