This is a left-over from "f4ec5e26 vfio: Add host side DMA window
capabilities", which added support to more than one DMA window.

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>