CVE-2026-64291 iommufd: Set veventq_depth upper bound

In the Linux kernel, the following vulnerability has been resolved: iommufd: Set veventqdepth upper bound iommufdveventqalloc accepts any !0 veventqdepth from userspace, with an upper bound at U32MAX. This leaves a vulnerability where userspace can allocate excessively large queues to exhaust...