This makes vfio_get_region_info_cap() to be used in quirks.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Message-Id: <20190307050518.64968-3-aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>