Needed to prevent display corruption in high res panels.

v2: use correct unit names (Rodrigo)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Tested-by: NUlrich Drepper <drepper@gmail.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>