fbdev: Fix unregistering of framebuffers without device
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 v5.16.20 by commit de33df481545974ba47c46f05194e769e4307843, it was introduced in version v5.16.19 by commit 9565a3b5203a4d57acbc1d0e981c6df71864b4ab. For more details please see the references link.