drm/bridge: lvds-codec: Add "lvds-decoder" support

Add support for transparent LVDS decoders by adding a new
compatible string ("lvds-decoder") to the driver.
This patch also adds member connector_type to struct lvds_codec,
and that's because LVDS decoders have a different connector type
from LVDS encoders. We fill this new member up with the data
matching the compatible string.

Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[Fix pointer to int cast warning]
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191217230753.2999-1-laurent.pinchart+renesas@ideasonboard.com