cdrom_open(), cdrom_release(), cdrom_ioctl() and cdrom_media_changed()
got an additional argument - struct cdrom_device_info *.  Drivers that used
to have them as methods are using wrappers that pass right cdrom_device_info.
Existing callers (in ide-cd.c) updated.  pcd.c, mcdx.c, sbpcd.c and sr.c
got ->private_data in their disks pointing to relevant objects.  Since all
callers of cdrom_find_device() are gone, it got removed.  Since all users
of cdrom_device_info->dev are gone, it's not set anymore (and got removed).