libata: correct handling of TSS DVD

Devices that misreport the validity bit for word 93 look like SATA.  If
they are on the blacklist then we must not test for SATA but assume 40 wire
in the 40 wire case (The TSSCorp reports 80 wire on SATA it seems!)

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>