CVE-2026-68114 drm/amdgpu/gfx12.1: replace BUG_ON() with WARN_ON()

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu/gfx12.1: replace BUGON with WARNON There's no need to crash the kernel for these cases. cherry picked from commit e4d99e04b2e9b13b97d3b17804c735f62689db23...