dt-bindings: can: rcar_can: document r8a774b1 support

Document RZ/G2N (r8a774b1) SoC specific bindings.
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1570717560-7431-2-git-send-email-fabrizio.castro@bp.renesas.comSigned-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

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

@@ -7,6 +7,7 @@ Required properties:
 	      "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-r8a774b1" if CAN controller is a part of R8A774B1 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.
 	      "renesas,can-r8a7779" if CAN controller is a part of R8A7779 SoC.
@@ -36,8 +37,8 @@ Required properties:
 - pinctrl-0: pin control group to be used for this controller.
 - pinctrl-names: must be "default".
 
-Required properties for R8A774A1, R8A774C0, R8A7795, R8A7796, R8A77965,
-R8A77990, and R8A77995:
+Required properties for R8A774A1, R8A774B1, R8A774C0, R8A7795, R8A7796,
+R8A77965, R8A77990, and R8A77995:
 For the denoted SoCs, "clkp2" can be CANFD clock. This is a div6 clock and can
 be used by both CAN and CAN FD controller at the same time. It needs to be
 scaled to maximum frequency if any of these controllers use it. This is done