usb: tag xhci as hotpluggable

Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb/hcd-xhci.c

@@ -3874,7 +3874,6 @@ static void xhci_class_init(ObjectClass *klass, void *data)
     dc->vmsd    = &vmstate_xhci;
     dc->props   = xhci_properties;
     dc->reset   = xhci_reset;
-    dc->hotpluggable   = false;
     set_bit(DEVICE_CATEGORY_USB, dc->categories);
     k->init         = usb_xhci_initfn;
     k->exit         = usb_xhci_exit;