ide-floppy: convert to using the new atapi_flags (take 2)

while at it, remove PC_FLAG_ZIP_DRIVE from the packed command flags altogether
and query the drive type through drive->atapi_flags.

v2:
ide-floppy fix.

There should be no functionality change resulting from this patch.

[bart: IDE_FLAG_* -> IDE_AFLAG_*, dev_flags -> atapi_flags]

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