drm: bridge: Add LVDS encoder driver

The LVDS encoder driver is a DRM bridge driver that supports the
parallel to LVDS encoders that don't require any configuration. The
driver thus doesn't interact with the device, but creates an LVDS
connector for the panel and exposes its size and timing based on
information retrieved from DT.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170302104728.7150-3-laurent.pinchart+renesas@ideasonboard.com