ide-floppy: zero out the whole struct ide_atapi_pc on init

This is a precaution just to make sure a new pc is clean when allocated.

There should be no functional change introduced by this patch.

[bart: ported it over IDE changes]

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