dt-bindings: irqchip: renesas,irqc: Add r8a779g0 support

Document support for the Interrupt Controller for External Devices
(INT-EX) in the Renesas R-Car V4H (R8A779G0) SoC.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/4fdb6ff47f62814aab3b06efd1d4c2d7de83b109.1664368373.git.geert+renesas@glider.be

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

@@ -37,6 +37,7 @@ properties:
           - renesas,intc-ex-r8a77990    # R-Car E3
           - renesas,intc-ex-r8a77995    # R-Car D3
           - renesas,intc-ex-r8a779a0    # R-Car V3U
+          - renesas,intc-ex-r8a779g0    # R-Car V4H
       - const: renesas,irqc
 
   '#interrupt-cells':