libata: ahci: Add support for Enmotus Bobcat device.

commit 7f9c9f8e24590e7dcd26ca408458c43df5b83e61 upstream.

Silicon does not support standard AHCI BAR assignment.  Add
vendor/device exception to force BAR 2.

Signed-off-by: Hugh Daschbach <hugh.daschbach@enmotus.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>