staging: rtl8192e: Remove create_workqueue()

With conccurency managed workqueues, use of dedicated workqueues can
be replaced by system_wq. Drop wq by using system_wq.

Since there are multiple work items per rtllib but they do not need to
be ordered, increase of concurrency by switching to system_wq should
not break anything.

All work items are sync canceled on rtllib_stop_protocol() so it is
guaranteed that no work is running when rtl92e_disable/reset/restart
functions are called.

Signed-off-by: Amitoj Kaur Chawla <amitoj1606@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>