pata_via: Handle laptops via DMI

Oh the joy of saving a fraction of a cent using short 40 wire cables and
not faking 80wire

Teach the VIA driver that there are some systems we need to know are
magically wired for high speeds.

Signed-off-by: Alan Cox <alan@redhat.com>
Tested-by: Francis Russell <FrancisRussell@btinternet.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>