Documentation/ABI: clean up sysfs-class-pktcdvd

Clean up the sysfs documentation such that it is in the same format as
described in Documentation/ABI/README. Mainly, the patch moves the
attribute names to the 'What:' field. This might be useful for scripting
and tracking changes in the ABI.

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>