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 v5.15.34 by commit 2388f826cdc9af2651991adc0feb79de9bdf2232, it was introduced in version v5.15.33 by commit c894ac44786cfed383a6c6b20c1bfb12eb96018a. For more details please see the references link.