[libata] pata_via: support VX855, future chips whose IDE controller use 0x0571

It supports VX855 and future chips whose IDE controller uses PCI ID 0x0571.

Signed-off-by: Joseph Chan <josephchan@via.com.tw>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>