drm/gud: NUL-terminate TV mode names read from the device

In the Linux kernel, the following vulnerability has been resolved: drm/gud: NUL-terminate TV mode names read from the device gud_connector_add_tv_mode() reads a buffer of fixed-size mode names from the USB device and passes pointers into it to drm_mode_create_tv_properties_legacy(), which calls strlen() on each one. Nothing guarantees the device NUL-terminates a name, so strlen() can run past the end of a slot and, for the last mode, past the end of the allocation. Terminate each name at the end of its slot before use.

Where it's fixed