[PATCH] ata_piix: add ICH6/7/8 to Kconfig

Ata_piix's Kconfig entry still refers only to ICH5, while it supports ICH6
through 8. This creates confusion with people who are looking to see
if their newer SATA enabled motherboards are supported. The
following patch makes this clear.

Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>