ahci: Gigabyte GA-MA69VM-S2 can't do 64bit DMA

Gigabyte GA-MA69VM-S2 can't do 64bit DMA either.  It's yet unknown
whether recent BIOS fixes the problem.  Blacklist regardless of BIOS
revisions for now.

Sandor Bodo-Merle reported and provided the initial patch for this
issue.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Sandor Bodo-Merle <sbodomerle@gmail.com>
Cc: Shane Huang <shane.huang@amd.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>