cdrom: debug info changes, Beurer glucometer support

[Diego Elio PettenÃ]

Hello,

I've been hacking around the cdrom driver so that I could get Linux to
mount and access the virtual CD device used by the Beurer GL50 evo
glucometer. The device is fairly quirky and goes into a reset cycle on a
vanilla kernel.

Since I had no idea how to get to the right changes at first, I ended up
playing with the debug information a fair amount at first, and I thought it
would be nice to clean it up to modern standard. Joe Perches suggested
removing debug output redundant with ftrace (which was actually quite
useful to find the right places to change.)

HTH!