drivers: staging: r8188eu: Fix sleep-in-atomic-context bug in rtw_join_timeout_handler

drivers: staging: r8188eu: Fix sleep-in-atomic-context bug in rtw_join_timeout_handler

The rtw_join_timeout_handler() is a timer handler that
runs in atomic context, but it could call msleep().
As a result, the sleep-in-atomic-context bug will happen.
The process is shown below:

     (atomic context)
rtw_join_timeout_handler
 _rtw_join_timeout_handler
  rtw_do_join
   rtw_select_and_join_from_scanned_queue
    rtw_indicate_disconnect
     rtw_lps_ctrl_wk_cmd
      lps_ctrl_wk_hdl
       LPS_Leave
        LPS_RF_ON_check
         msleep //sleep in atomic context

Fix by removing msleep() and replacing with mdelay().

Fixes: 15865124feed ("staging: r8188eu: introduce new core dir for RTL8188eu driver")
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Link: https://lore.kernel.org/r/20221018083424.79741-1-duoming@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>