Bluetooth: btusb: mediatek: change the conditions for ISO interface

commit defc33b5 upstream.

Change conditions for Bluetooth driver claiming and releasing usb
ISO interface for MediaTek ISO data transmission.

Signed-off-by: Chris Lu <chris.lu@mediatek.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Cc: Fedor Pchelkin <boddah8794@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>