Bluetooth: btusb: mediatek: add intf release flow when usb disconnect

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: btusb: mediatek: add intf release flow when usb disconnect MediaTek claim an special usb intr interface for ISO data transmission. The interface need to be released before unregistering hci device when usb disconnect. Removing BT usb dongle without properly releasing the interface may cause Kernel panic while unregister hci device.