dbus: Use new bus name, object and interface

The new interface is a more typical use of DBus, exposing multiple
methods for the functions that are available on the object. The legacy
interface by comparison exposed only one method whose arguments selected
sub-commands to be executed. The legacy approach is not terribly
discoverable and leads to a lack of clarity in the client code. The
legacy approach also obscured the implementation with its use of `struct
mbox_dbus_msg`. The new interface wraps around the existing helpers and
so also deals with `struct mbox_dbus_msg`, but this can at least be
removed in the future.

Change-Id: I7113ed8fd2324bf3fb049d8d20acb3fd7fba6de3
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/control_legacy.c b/control_legacy.c
index d0e1e1f..08ac6f3 100644
--- a/control_legacy.c
+++ b/control_legacy.c
@@ -5,7 +5,7 @@
 
 #include "common.h"
 #include "dbus.h"
-#include "mboxd_dbus.h"
+#include "control_dbus.h"
 #include "mbox.h"
 
 /*