ARM: dts: renesas: iwg22d-sodimm: Use interrupts-extended for port expander

Use the more concise interrupts-extended property to fully describe the
interrupt.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/835b5e851939f6fa2c9567d6850a7e0c2574c1c7.1728045620.git.geert+renesas@glider.be