irqchip/renesas-rzg2l: Use local dev pointer in rzg2l_irqc_common_init()

Replace direct references to `&pdev->dev` with the local `dev` pointer
in rzg2l_irqc_common_init() to avoid redundant dereferencing.

Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/all/20250212182034.366167-2-fabrizio.castro.jz@renesas.com