ide-tape: cleanup the remaining codestyle issues

... thus decreasing checkpatch.pl errors to 0.

Bart:
- remove needless function prototypes while at it
- remove needless parentheses while at it
- add missing KERN_ level to ide_tape_probe()
- other minor fixups

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>