Bluetooth: btsdio: fix use after free bug in btsdio_remove due to race condition

In btsdio_probe, the data->work is bound with btsdio_work. It will be
started in btsdio_send_frame.

If the btsdio_remove runs with a unfinished work, there may be a race
condition that hdev is freed but used in btsdio_work. Fix it by
canceling the work before do cleanup in btsdio_remove.

Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>