sdbus++: hook interface into server bindings

sdbusplus::server::interface class is used to register an
interface on the dbus.  Utilize this in the generated server
bindings by containing an instance of 'interface' and creating
a proper constructor.

Change-Id: I068bbe1c370a55053193b89931fb8f7da740de52
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/tools/templates/interface.mako.server.cpp b/tools/templates/interface.mako.server.cpp
index 16f7f43..590ee6b 100644
--- a/tools/templates/interface.mako.server.cpp
+++ b/tools/templates/interface.mako.server.cpp
@@ -13,6 +13,13 @@
 namespace ${s}
 {
     % endfor
+
+${classname}::${classname}(bus::bus& bus, const char* path)
+        : _${"_".join(interface.name.split('.'))}_interface(
+                bus, path, _interface, _vtable, this)
+{
+}
+
     % for m in interface.methods:
 ${ m.cpp_prototype(loader, interface=interface, ptype='callback-cpp') }
     % endfor