sb_init_dio_done_wq is also used by the iomap code, so move it to
super.c in preparation for building direct-io.c conditionally.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NEric Biggers <ebiggers@google.com>
Reviewed-by: NJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230125065839.191256-2-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>