drm/radeon: add primary dac adj quirk for R200 board

commit e8fc4137 upstream.

vbios values are wrong leading to colors that are
too bright.  Use the default values instead.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>