dt-bindings: interrupt-controller: Add Renesas RZ/G2L Interrupt Controller

Add DT bindings for the Renesas RZ/G2L Interrupt Controller.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220707182314.66610-3-prabhakar.mahadev-lad.rj@bp.renesas.com