dt-bindings: can: rcar_can: document r8a77470 support

Document SoC specific bindings for R-Car RZ/G1C(r8a77470) SoC.
Signed-off-by: Cao Van Dong <cv-dong@jinso.co.jp>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Documentation/devicetree/bindings/net/can/rcar_can.txt

@@ -5,6 +5,7 @@ Required properties:
 - compatible: "renesas,can-r8a7743" if CAN controller is a part of R8A7743 SoC.
 	      "renesas,can-r8a7744" if CAN controller is a part of R8A7744 SoC.
 	      "renesas,can-r8a7745" if CAN controller is a part of R8A7745 SoC.
+	      "renesas,can-r8a77470" if CAN controller is a part of R8A77470 SoC.
 	      "renesas,can-r8a774a1" if CAN controller is a part of R8A774A1 SoC.
 	      "renesas,can-r8a774c0" if CAN controller is a part of R8A774C0 SoC.
 	      "renesas,can-r8a7778" if CAN controller is a part of R8A7778 SoC.