mISDN: fix possible use-after-free in HFC_cleanup()
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v4.4.276 by commit 49331c07ef0f8fdfa42b30ba6a83a657b29d7fbe. For more details please see the references link.