driver: uio: fix possible use-after-free in __uio_register_device

mainline inclusion
from mainline-5.x
commit: 221a1f4a
category: bugfix
bugzilla: NA
CVE: NA

---------------------------

In uio_dev_add_attributes() error handing case, idev is used after
device_unregister(), in which 'idev' has been released, touch idev cause
use-after-free.

Fixes: a93e7b33 ("uio: Prevent device destruction while fds are open")
Signed-off-by: Liu Jian <liujian56@huawei.com>
Reviewed-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>