cdrom: mark CDROMGETSPINDOWN/CDROMSETSPINDOWN obsolete

cdrom: mark CDROMGETSPINDOWN/CDROMSETSPINDOWN obsolete

These were only implemented by the IDE CD driver, which has since
been removed.  Given that nobody is likely to create new CD/DVD
hardware (and associated drivers) we can mark these appropriately.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Link: https://lore.kernel.org/all/20220427132436.12795-3-paul.gortmaker@windriver.com
Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20220515205833.944139-4-phil@philpotter.co.uk
Signed-off-by: Jens Axboe <axboe@kernel.dk>