ata_piix: Remove ugly layering violation

A while ago I modified the libata code so that drivers can return -ENOENT
for unknown ports not fiddle with the EH flags and print stuff directly.
Somewhere along the line ata_piix didn't get fully converted.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>