Only bfq needs to code to track icq, so make it conditional.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-12-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>