dt-bindings: display: renesas: lvds: Document r8a774a1 bindings

Document the RZ/G2M (R8A774A1) LVDS bindings.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

Documentation/devicetree/bindings/display/bridge/renesas,lvds.txt

@@ -9,6 +9,7 @@ Required properties:
 - compatible : Shall contain one of
   - "renesas,r8a7743-lvds" for R8A7743 (RZ/G1M) compatible LVDS encoders
   - "renesas,r8a7744-lvds" for R8A7744 (RZ/G1N) compatible LVDS encoders
+  - "renesas,r8a774a1-lvds" for R8A774A1 (RZ/G2M) compatible LVDS encoders
   - "renesas,r8a774c0-lvds" for R8A774C0 (RZ/G2E) compatible LVDS encoders
   - "renesas,r8a7790-lvds" for R8A7790 (R-Car H2) compatible LVDS encoders
   - "renesas,r8a7791-lvds" for R8A7791 (R-Car M2-W) compatible LVDS encoders