pata_via: Fix 6410 misdetect

The discrete VIA ATA chips don't have 0x40 enable bits. We check that
properly in one location but not another. This causes some users 6410
RAID cards to be incorrectly skipped.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>