SiS965 and SiS180 chips must support slave mode,
SiS965L and SiS964 chips must not support slave mode.

SCR_STATUS for SATA ports in powerdown state fixed.
Now returning 0x0113 instead of 0x0117. Avoids problem
on detecting sata_sis controller.
Signed-off-by: Uwe Koziolek <uwe.koziolek@gmx.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>