staging: rtl8712: get rid of flush_scheduled_work

stable inclusion
from stable-5.10.58
commit e468a357af68ca15d99530f8f760fb6799eb762d
bugzilla: 176984 https://gitee.com/openeuler/kernel/issues/I4E2P4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e468a357af68ca15d99530f8f760fb6799eb762d



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

commit 9be550ee upstream.

This patch is preparation for following patch for error handling
refactoring.

flush_scheduled_work() takes (wq_completion)events lock and
it can lead to deadlock when r871xu_dev_remove() is called from workqueue.
To avoid deadlock sutiation we can change flush_scheduled_work() call to
flush_work() call for all possibly scheduled works in this driver,
since next patch adds device_release_driver() in case of fw load failure.

Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/6e028b4c457eeb7156c76c6ea3cdb3cb0207c7e1.1626895918.git.paskripkin@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>