They don't always appear as AHCI class devices but instead as IDE class.
Based on an initial patch by Hiroaki Nito
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=42804
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>