media: dt-bindings: media: rcar_vin: 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/rcar_vin.txt

@@ -13,6 +13,7 @@ on Gen3 and RZ/G2 platforms to a CSI-2 receiver.
    - "renesas,vin-r8a7743" for the R8A7743 device
    - "renesas,vin-r8a7744" for the R8A7744 device
    - "renesas,vin-r8a7745" for the R8A7745 device
+   - "renesas,vin-r8a774a1" for the R8A774A1 device
    - "renesas,vin-r8a774c0" for the R8A774C0 device
    - "renesas,vin-r8a7778" for the R8A7778 device
    - "renesas,vin-r8a7779" for the R8A7779 device