irqchip/renesas-rzg2l: Align struct member names to tabs

Align struct member names to tabs to follow the requirements from
maintainer-tip file. 3 tabs were used at the moment as the next commits
will add a new member which requires 3 tabs for a better view.
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20231120111820.87398-4-claudiu.beznea.uj@bp.renesas.com