comedi: ni_usb6501: fix NULL-deref in command paths
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 v4.14.255 by commit df7b1238f3b599a0b9284249772cdfd1ea83a632, it was introduced in version v3.18 by commit a03bb00e50ab4c07107da58a52a0bff7943f360c. For more details please see the references link.