The !CONFIG_IO_URING signature is wrong, fix that up. The non stub
signature got updated for the io_br_sel changes that happened before
this patch went in, but the stub one did not.
Fixes: 620a50c927 ("io_uring: uring_cmd: add multishot support")
Signed-off-by: Jens Axboe <axboe@kernel.dk>