When we use virtio-vga with a big-endian guest,
the mouse pointer disappears.

To fix that, on big-endian use DRM_FORMAT_BGRA8888
instead of DRM_FORMAT_ARGB8888.
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170405080915.823-1-lvivier@redhat.comSigned-off-by: Gerd Hoffmann <kraxel@redhat.com>