Convert sata_via to new EH.  vt6420 used ATA_FLAG_SRST while vt6421
used ATA_FLAG_SATA_RESET.  This difference seems to be an accident
rather than intended.  This patch makes both flavors use
ata_bmdma_error_handler() which makes use of both SRST and SATA
hardreset.  This behavior change is intended and if it breaks
anything, it should be very easy to spot.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>