u2f-passthru: put it into the 'misc' category

The category of the u2f-passthru device is not set, put it into the 'misc'
category.

Signed-off-by: Gan Qixin <ganqixin@huawei.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Message-Id: <20201130083630.2520597-10-ganqixin@huawei.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

hw/usb/u2f-passthru.c

@@ -534,6 +534,7 @@ static void u2f_passthru_class_init(ObjectClass *klass, void *data)
     dc->desc = "QEMU U2F passthrough key";
     dc->vmsd = &u2f_passthru_vmstate;
     device_class_set_props(dc, u2f_passthru_properties);
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 }
 
 static const TypeInfo u2f_key_passthru_info = {