io-wq: move nr_running and worker_refs out of wqe->lock protection

We don't need to protect nr_running and worker_refs by wqe->lock, so
narrow the range of raw_spin_lock_irq - raw_spin_unlock_irq

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210810125554.99229-1-haoxu@linux.alibaba.com


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