CVE-2025-40288 drm/amdgpu: Fix NULL pointer dereference in VRAM logic for APU devices

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Fix NULL pointer dereference in VRAM logic for APU devices Previously, APU platforms and other scenarios with uninitialized VRAM managers triggered a NULL pointer dereference in ttmresourcemanagerusage. The root cause...