drm/radeon: fix a possible null pointer dereference
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 v4.14.283 by commit 16a0f0b63c4c7eb46fc4c3f00bf2836e6ee46a9f. For more details please see the references link.