ata_piix: enable 32bit PIO on SATA piix

Commit 871af121

 enabled 32bit PIO for
PATA piix but didn't for SATA.  There's no reason not to use 32bit PIO
on SATA piix.  Enable it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>