cdrom: remove obsolete TODO list

The TODO list in drivers/cdrom/cdrom.c has a single entry containing
obsolete information, unchanged since the first git commit over 17 years
ago, and probably longer. Remove this list from the comment to prevent
confusion in future.

Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
Link: https://lore.kernel.org/r/20220515205833.944139-6-phil@philpotter.co.uk


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