dbus/dbusconfiguration: add missing asio header

Signed-off-by: Patrick Venture <venture@google.com>
Change-Id: I286f2202c0612f93cd48a050ee72be565f35e2db
diff --git a/dbus/dbusconfiguration.hpp b/dbus/dbusconfiguration.hpp
index f9c3bcf..fc119e8 100644
--- a/dbus/dbusconfiguration.hpp
+++ b/dbus/dbusconfiguration.hpp
@@ -17,6 +17,7 @@
 #pragma once
 #include "conf.hpp"
 
+#include <boost/asio/steady_timer.hpp>
 #include <sdbusplus/bus.hpp>
 
 namespace pid_control