staging: rtl8192e: Exclude scan_mutex in rtllib_softmac_stop_scan

Exclude scan_mutex from cancel_delayed_work_sync(&ieee->softmac_scan_wq) as
ieee->softmac_scan_wq takes scan_mutex as well.

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/20230514204033.GA20187@matrix-ESPRIMO-P710


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>