Revert "io_uring: fix IO hang in io_wq_put_and_exit from do_exit()"

Revert "io_uring: fix IO hang in io_wq_put_and_exit from do_exit()"

This reverts commit b484a40dc1f16edb58e5430105a021e1916e6f27.

This commit cancels all requests with io-wq, not just the ones from the
originating task. This breaks use cases that have thread pools, or just
multiple tasks issuing requests on the same ring. The liburing
regression test for this also shows that problem:

$ test/thread-exit.t
cqe->res=-125, Expected 512

where an IO thread gets its request canceled rather than complete
successfully.

Signed-off-by: Jens Axboe <axboe@kernel.dk>