blk-mq: remove unused queue mapping helpers

There are no users left of the pci and virtio queue mapping helpers.
Thus remove them.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Link: https://lore.kernel.org/r/20241202-refactor-blk-affinity-helpers-v6-8-27211e9c2cd5@kernel.org


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