Bluetooth: btusb: Use cmd_timeout to reset Realtek device

Realtek Bluetooth controller provides a BT_DIS reset pin for hardware
reset of it. The cmd_timeout is helpful on Realtek bluetooth controller
where the firmware gets stuck.

Signed-off-by: Alex Lu <alex_lu@realsil.com.cn>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>