core: move physical device checking into the manager

It turns out that the manager needs to know about the physical
device so we can prevent multiple plugins from claiming ports on
the same modem.

src/mm-plugin.h

@@ -70,6 +70,7 @@ struct _MMPlugin {
     MMPluginSupportsResult (*supports_port)  (MMPlugin *self,
                                               const char *subsys,
                                               const char *name,
+                                              const char *physdev_path,
                                               MMSupportsPortResultFunc callback,
                                               gpointer user_data);
 
@@ -104,6 +105,7 @@ const char *mm_plugin_get_name   (MMPlugin *plugin);
 MMPluginSupportsResult mm_plugin_supports_port  (MMPlugin *plugin,
                                                  const char *subsys,
                                                  const char *name,
+                                                 const char *physdev_path,
                                                  MMSupportsPortResultFunc callback,
                                                  gpointer user_data);