drm/panel: simple: Fix the lt089ac29000 bus_format

drm/panel: simple: Fix the lt089ac29000 bus_format

The lt089ac29000 panel is an LVDS panel, not a DPI one. Fix the
definition to reflect this fact.

v10:
* Add changelog to the commit message

v8 -> v9:
* No changes

v7:
* New patch

Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200128135514.108171-12-boris.brezillon@collabora.com