CVE-2026-46309 drm/xe/uapi: Reject coh_none PAT index for CPU cached memory in madvise

In the Linux kernel, the following vulnerability has been resolved: drm/xe/uapi: Reject cohnone PAT index for CPU cached memory in madvise Add validation in xevmmadviseioctl to reject PAT indices with XECOHNONE coherency mode when applied to CPU cached memory. Using cohnone with CPU cached buffer...