[BUG] kaweth: a possible sleep-in-atomic bug in kaweth_start_xmit

According to drivers/net/usb/kaweth.c, the driver may sleep under a spinlock.
The function call path is:
kaweth_start_xmit (acquire the spinlock)
  kaweth_async_set_rx_mode
    kaweth_control
      kaweth_internal_control_msg
        usb_start_wait_urb
          wait_event_timeout --> may sleep
          usb_kill_urb --> may sleep

I do not find a good way to fix it, so I only report.
This possible bug is found by my static analysis tool (DSAC) and checked by my code review.


Thanks,
Jia-Ju Bai