ARM: dts: r8a7743: Convert to new LVDS DT bindings

The internal LVDS encoder now has DT bindings separate from the DU. Port
the device tree over to the new model.

Fixes: c6a27fa4

 ("drm: rcar-du: Convert LVDS encoder code to bridge driver")
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>