drm/radeon/kms: disable frac fb dividers for rs6xx

Should fix fdo bug 28331:
https://bugs.freedesktop.org/show_bug.cgi?id=28331

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
1 file changed