ide: unify interrupt reason checking

Add ide_check_ireason() function that handles all ATAPI devices.
Reorganize all unlikely cases in ireason checking further down in the
code path.

In addition, add PFX for printks originating from ide-atapi. Finally,
remove ide_cd_check_ireason.

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