engines/io_uring: don't mess with non power-of-2 queue depth

engines/io_uring: don't mess with non power-of-2 queue depth

io_uring needs the rings to be a power-of-2 in sizing, but it does not
need to be messing with the queue depth driven to the device. Rather
than round everything up, only round up the API parts.

Reported-by: Riley Thomasson <riley@purestorage.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>