elevator: use list_{first,prev,next}_entry
elevator: use list_{first,prev,next}_entry

To make the intention clearer, use list_{first,prev,next}_entry
instead of list_entry.

Signed-off-by: Geliang Tang <d12999005f6151b9468b6f2bd6d86bf9f7b59e02@163.com>
Signed-off-by: Jens Axboe <cd8c6775e60d6f67a6984377324e5290df3d5358@fb.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs