Segmentation fault when canceling paused jobs

https://github.com/intel/QAT_Engine/blob/26b4d6c34f32ac3bd21ebb78afc4c7428a70b1f8/qat_events.c#L289 use a pointer to ASYNC_JOB to get wait_ctx each time the driver ready, but wait_ctx may be got freed already when the async job canceled after received ASYNC_PAUSE in the main thread.
ASYNC_JOB doesn't have any protection for reusing wait_ctx across threads.