CVE-2026-89814 drm/amdgpu: clamp the isolation index for rings outside a partition

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: clamp the isolation index for rings outside a partition adev-isolation has one slot per partition, but a ring that is not assigned to one keeps AMDGPUXCPNOPARTITION, which is 0, so indexing the array with it is out of...