CVE-2026-23467 drm/i915/dmc: Fix an unlikely NULL pointer deference at probe

In the Linux kernel, the following vulnerability has been resolved: drm/i915/dmc: Fix an unlikely NULL pointer deference at probe inteldmcupdatedc6allowedcount oopses when DMC hasn't been initialized, and dmc is thus NULL. That would be the case when the call path is intelpowerdomainsinithw -...