drm: panel: Set connector type for LP120UP1

The LP120UP1 is a eDP panel, set the connector type accordingly.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200416164404.2418426-1-enric.balletbo@collabora.com