io_uring: use TWA_SIGNAL for task_work uncondtionally

io_uring: use TWA_SIGNAL for task_work uncondtionally

An earlier commit:

b7db41c9e03b ("io_uring: fix regression with always ignoring signals in io_cqring_wait()")

ensured that we didn't get stuck waiting for eventfd reads when it's
registered with the io_uring ring for event notification, but we still
have cases where the task can be waiting on other events in the kernel and
need a bigger nudge to make forward progress. Or the task could be in the
kernel and running, but on its way to blocking.

This means that TWA_RESUME cannot reliably be used to ensure we make
progress. Use TWA_SIGNAL unconditionally.

Cc: [email protected] # v5.7+
Reported-by: Josef <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>