dt-bindings: can: renesas,rcar-canfd: document r8a77961 support

This patch adds documentation for the r8a77961 to the
renesas,rcar-canfd binding.

Link: https://lore.kernel.org/all/20220401153743.77871-1-wsa+renesas@sang-engineering.com
Cc: devicetree@vger.kernel.org
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

Documentation/devicetree/bindings/net/can/renesas,rcar-canfd.yaml

@@ -23,6 +23,7 @@ properties:
               - renesas,r8a774e1-canfd     # RZ/G2H
               - renesas,r8a7795-canfd      # R-Car H3
               - renesas,r8a7796-canfd      # R-Car M3-W
+              - renesas,r8a77961-canfd     # R-Car M3-W+
               - renesas,r8a77965-canfd     # R-Car M3-N
               - renesas,r8a77970-canfd     # R-Car V3M
               - renesas,r8a77980-canfd     # R-Car V3H