usb-hub: convert init to realize

In this way, all the implementations now use
error_setg instead of error_report for reporting error.
Signed-off-by: NGonglei <arei.gonglei@huawei.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb/dev-hub.c

@@ -511,15 +511,15 @@ static USBPortOps usb_hub_port_ops = {
     .complete = usb_hub_complete,
 };
 
-static int usb_hub_initfn(USBDevice *dev)
+static void usb_hub_realize(USBDevice *dev, Error **errp)
 {
     USBHubState *s = DO_UPCAST(USBHubState, dev, dev);
     USBHubPort *port;
     int i;
 
     if (dev->port->hubcount == 5) {
-        error_report("usb hub chain too deep");
-        return -1;
+        error_setg(errp, "usb hub chain too deep");
+        return;
     }
 
     usb_desc_create_serial(dev);
@@ -533,7 +533,6 @@ static int usb_hub_initfn(USBDevice *dev)
         usb_port_location(&port->port, dev->port, i+1);
     }
     usb_hub_handle_reset(dev);
-    return 0;
 }
 
 static const VMStateDescription vmstate_usb_hub_port = {
@@ -564,7 +563,7 @@ static void usb_hub_class_initfn(ObjectClass *klass, void *data)
     DeviceClass *dc = DEVICE_CLASS(klass);
     USBDeviceClass *uc = USB_DEVICE_CLASS(klass);
 
-    uc->init           = usb_hub_initfn;
+    uc->realize        = usb_hub_realize;
     uc->product_desc   = "QEMU USB Hub";
     uc->usb_desc       = &desc_hub;
     uc->find_device    = usb_hub_find_device;