drm/xe: Fix null pointer dereference in devcoredump cleanup

In the Linux kernel, the following vulnerability has been resolved: drm/xe: Fix null pointer dereference in devcoredump cleanup In xe_devcoredump_snapshot_free(), ss->gt may be NULL when the snapshot was never fully populated (e.g., when cleanup is triggered without a prior capture). Guard the xe_guc_capture_put_matched_nodes() call with IS_ERR_OR_NULL() to prevent a null dereference. In xe_devcoredump_free(), the deferred work is only queued when a coredump is captured, so guard cancel_work_sync() with a check on coredump->captured.

Where it's fixed