ahci: filter FPDMA non-zero offset enable for Aspire 3810T

Curiously, Aspire 3810T issues many SATA feature enable commands via
_GTF, of which one is invalid and another is not supported by the
drive.  In the process, it also enables FPDMA non-zero offset.
However, the feature also needs to be supported and enabled from the
controller and it's wrong to enable it from _GTF unless the controller
can do it by default.

Currently, this ends up enabling FPDMA non-zero offset only on the
drive side leading to NCQ command failures and eventual disabling of
NCQ.  This patch makes libata filter out FPDMA non-zero offset enable
for the machine.

This was reported by Marcus Meissner in bnc#522790.

  https://bugzilla.novell.com/show_bug.cgi?id=522790



Reported-by: Marcus Meissner <meissner@novell.com>

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