drivers/cdrom: use pr_<level>

- add pr_fmt.

- convert printks to pr_<level>

- add if (0) and printf argument checking to cdinfo

- coalesce consecutive printks to single pr_

- fix a typo "back ground" to "background"

- convert printks without level to pr_info

- remove VIOCD_ prefixes and use pr_fmt/pr_<level>

- add a missing newline to an OS/400 message

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Folded in tab indentation fix from Andrew.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>