drm/panel: simple: Add support for Innolux G121I1-L01

The Innolux G121I1-L01 is a 12.1" TFT LCD panel and can be supported by
the simple-panel driver.

This panel is connected via LVDS and uses the data enable signal for
timing. Since HSYNC/VSYNC are ignored, the split between sync length and
porches is arbitrary, as long as the complete horizontal blanking interval
is 160 clocks, and the vertical blanking interval is 24 lines.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>