Teach the debug logging macro to differentiate between log levels based on the
type of debug level enabled specifically instead of a threshold-based one.
Thus, convert tape->debug_level to a bitmask that is written to over /proc.

Also,
- cleanup and simplify the debug macro thus removing a lot of code lines,
- get rid of unused debug levels,
- adjust the loglevel at several places where it was simply missing (e.g.
  idetape_chrdev_open())
- move the tape ptr initialization up in idetape_chrdev_open() so that we can
  use it in the debug_log macro earlier in the function.

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