drm/panel: simple: Add AVIC TM070DDH03 panel support

The Shanghai AVIC Optoelectronics TM070DDH03 is a 7" 1024x600 TFT LCD
panel connecting to a 24-bit RGB LVDS interface.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>