media: dt-bindings: media: rcar-csi2: Add r8a774a1 support

Document RZ/G2M (R8A774A1) SoC bindings.

The RZ/G2M SoC is similar to R-Car M3-W (R8A7796).
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Acked-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/devicetree/bindings/media/renesas,rcar-csi2.txt

@@ -8,6 +8,7 @@ R-Car VIN module, which provides the video capture capabilities.
 Mandatory properties
 --------------------
  - compatible: Must be one or more of the following
+   - "renesas,r8a774a1-csi2" for the R8A774A1 device.
    - "renesas,r8a774c0-csi2" for the R8A774C0 device.
    - "renesas,r8a7795-csi2" for the R8A7795 device.
    - "renesas,r8a7796-csi2" for the R8A7796 device.