Re-land "[shill] Add hardware address to Device objects."

Forgot some headers...

BUG=chromium-os:17744
TEST=unit

This reverts commit 0fda552b0fec3498403336acb9e89dd7799cac74.

Change-Id: I1cd05e47d29bc7ea2a065cabf1d81dd37f74c0f8
Reviewed-on: http://gerrit.chromium.org/gerrit/6270
Reviewed-by: Chris Masone <cmasone@chromium.org>
Tested-by: Chris Masone <cmasone@chromium.org>
diff --git a/wifi.h b/wifi.h
index 86969da..8a35e95 100644
--- a/wifi.h
+++ b/wifi.h
@@ -27,7 +27,8 @@
   WiFi(ControlInterface *control_interface,
        EventDispatcher *dispatcher,
        Manager *manager,
-       const std::string& link,
+       const std::string &link,
+       const std::string &address,
        int interface_index);
   virtual ~WiFi();
   virtual void Start();