ide-{floppy,tape}: move checking of ->failed_pc to ->callback

Move checking/resetting of ->failed_pc from ide*_pc_intr() to ->callback
as a preparation for adding generic ide_pc_intr() helper.

There should be no functional changes caused by this patch.

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