qdev: Eliminate duplicate reset

qbus_reset_all_fn was registered twice, so a lot of device reset
functions were also called twice when QEMU started.
Which was introduced by 80376c3fc2c38fdd45354e4b0eb45031f35587ed
This patch fixes it by making the main_system_bus creation not register
reset handler.

Cc: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Tested-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/qdev.c

@@ -36,6 +36,7 @@ static bool qdev_hot_removed = false;
 
 /* This is a nasty hack to allow passing a NULL bus to qdev_create.  */
 static BusState *main_system_bus;
+static void main_system_bus_create(void);
 
 DeviceInfo *device_info_list;
 
@@ -328,8 +329,7 @@ static int qdev_reset_one(DeviceState *dev, void *opaque)
 BusState *sysbus_get_default(void)
 {
     if (!main_system_bus) {
-        main_system_bus = qbus_create(&system_bus_info, NULL,
-                                      "main-system-bus");
+        main_system_bus_create();
     }
     return main_system_bus;
 }
@@ -784,6 +784,16 @@ BusState *qbus_create(BusInfo *info, DeviceState *parent, const char *name)
     return bus;
 }
 
+static void main_system_bus_create(void)
+{
+    /* assign main_system_bus before qbus_create_inplace()
+     * in order to make "if (bus != main_system_bus)" work */
+    main_system_bus = qemu_mallocz(system_bus_info.size);
+    main_system_bus->qdev_allocated = 1;
+    qbus_create_inplace(main_system_bus, &system_bus_info, NULL,
+                        "main-system-bus");
+}
+
 void qbus_free(BusState *bus)
 {
     DeviceState *dev;