io_uring: make __tctx_task_work_run() take an io_wq_work_list

io_uring: make __tctx_task_work_run() take an io_wq_work_list

The normal task_work logic doesn't really need it, as it always runs
all of the pending work. But for SQPOLL, it can now pass in its
retry_list which simplifies the tracking of split up task_work running.

This avoids passing io_wq_work_node around. Rather than pass in a list,
SQPOLL could re-add the leftover items to the generic task_work list.
But that requires re-locking the task_lock and using task_list for that,
whereas having a separate retry list allows for skipping those steps.
The downside is that now two lists need checking, but that's now it
was before as well.

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