drm/tegra: dc: Enable plane scaling filters

Currently resized plane produces a "pixelated" image which doesn't look
nice, especially in a case of a video overlay. Enable scaling filters that
significantly improve image quality of a scaled overlay.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>