Add properties for the default display resolution, pass
on that information to the guest so the driver can use it.

Also move up qxl_crc32() function so we don't need a
forward declaration.

Additionally guest driver updates are needed so the
guest driver will actually pick this up, which will
probably land in linux kernel 4.12.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20170421092234.8368-1-kraxel@redhat.com