vme: Use root_device_register() not underlined version

root_device_register and __root_device_register have exactly same
effect. Use the not underlined version to keep usage consistency.

Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Link: https://lore.kernel.org/r/20221206015033.125827-1-chenzhongjin@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>