Add exit callback to DeviceInfo.

This adds a exit callback for device destruction to DeviceInfo, so
we can hook cleanups into qdev device destruction.

Followup patches will put that into use.
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/qdev.c

@@ -245,6 +245,8 @@ void qdev_free(DeviceState *dev)
 #endif
         if (dev->info->reset)
             qemu_unregister_reset(dev->info->reset, dev);
+        if (dev->info->exit)
+            dev->info->exit(dev);
     }
     QLIST_REMOVE(dev, sibling);
     qemu_free(dev);

hw/qdev.h

@@ -108,6 +108,7 @@ BusState *qdev_get_child_bus(DeviceState *dev, const char *name);
 /*** Device API.  ***/
 
 typedef int (*qdev_initfn)(DeviceState *dev, DeviceInfo *info);
+typedef int (*qdev_exitfn)(DeviceState *dev);
 
 struct DeviceInfo {
     const char *name;
@@ -125,6 +126,7 @@ struct DeviceInfo {
 
     /* Private to qdev / bus.  */
     qdev_initfn init;
+    qdev_exitfn exit;
     BusInfo *bus_info;
     struct DeviceInfo *next;
 };