dt-bindings: display: renesas,du: Document the r8a7742 bindings

Document the RZ/G1H (R8A7742) SoC in the R-Car DU bindings.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Documentation/devicetree/bindings/display/renesas,du.txt

@@ -3,6 +3,7 @@
 Required Properties:
 
   - compatible: must be one of the following.
+    - "renesas,du-r8a7742" for R8A7742 (RZ/G1H) compatible DU
     - "renesas,du-r8a7743" for R8A7743 (RZ/G1M) compatible DU
     - "renesas,du-r8a7744" for R8A7744 (RZ/G1N) compatible DU
     - "renesas,du-r8a7745" for R8A7745 (RZ/G1E) compatible DU
@@ -68,6 +69,7 @@ corresponding to each DU output.
 
                         Port0          Port1          Port2          Port3
 -----------------------------------------------------------------------------
+ R8A7742 (RZ/G1H)       DPAD 0         LVDS 0         LVDS 1         -
  R8A7743 (RZ/G1M)       DPAD 0         LVDS 0         -              -
  R8A7744 (RZ/G1N)       DPAD 0         LVDS 0         -              -
  R8A7745 (RZ/G1E)       DPAD 0         DPAD 1         -              -