cdrom: remove the unused driver specific disc change ioctl

cdrom: remove the unused driver specific disc change ioctl

This was only used by the ide-cd driver, which went away in
commit b7fb14d3ac63 ("ide: remove the legacy ide driver")
so we might as well take advantage of that and get rid of
this hook as well.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: https://lore.kernel.org/all/20220427132436.12795-2-paul.gortmaker@windriver.com
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20220515205833.944139-3-phil@philpotter.co.uk
Signed-off-by: Jens Axboe <axboe@kernel.dk>