CVE-2026-68427 gpu: host1x: Fix use-after-free in host1x_bo_clear_cached_mappings

In the Linux kernel, the following vulnerability has been resolved: gpu: host1x: Fix use-after-free in host1xboclearcachedmappings host1xbounpin drops the last reference to the mapping and frees it, so we can't dereference mapping afterwards. The cache itself outlives the mapping, so use the cach...