CVE-2026-68263 drm/imagination: Fix double call to drm_sched_entity_fini()

In the Linux kernel, the following vulnerability has been resolved: drm/imagination: Fix double call to drmschedentityfini Call sequence of double call: pvrcontextdestroy pvrcontextkillqueues pvrqueuekill drmschedentitydestroy drmschedentityfini // here pvrcontextput...