dt-bindings: irqchip: renesas-irqc: Document r8a77980 support

Document R-Car V3H (AKA R8A77980) SoC bindings.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Documentation/devicetree/bindings/interrupt-controller/renesas,irqc.txt

@@ -17,6 +17,7 @@ Required properties:
     - "renesas,intc-ex-r8a7796" (R-Car M3-W)
     - "renesas,intc-ex-r8a77965" (R-Car M3-N)
     - "renesas,intc-ex-r8a77970" (R-Car V3M)
+    - "renesas,intc-ex-r8a77980" (R-Car V3H)
     - "renesas,intc-ex-r8a77995" (R-Car D3)
 - #interrupt-cells: has to be <2>: an interrupt index and flags, as defined in
   interrupts.txt in this directory