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 v4.14.253 by commit 37e4f57b22cc5ebb3f80cf0f74fdeb487f082367. For more details please see the references link.