isdn: mISDN: Fix sleeping function called from invalid context
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 v4.4.290 by commit 6f95c97e0f9d6eb39c3f2cb45e8fa4268d1b372b. For more details please see the references link.