isdn: cpai: check ctr->cnr to avoid array index out of bound
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 9b6b2db77bc3121fe435f1d4b56e34de443bec75. For more details please see the references link.