drm/panel: simple: Add NVD9128 as a simple panel

Add New Vision Display 7.0" 800 RGB x 480 TFT LCD panel

Signed-off-by: Fabien Lahoudere <fabien.lahoudere@collabora.co.uk>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>