pinctrl: renesas: pinctrl-rzg2l: Add IRQ domain to handle GPIO interrupt

Add IRQ domain to RZ/G2L pinctrl driver to handle GPIO interrupt.

GPIO0-GPIO122 pins can be used as IRQ lines but only 32 pins can be
used as IRQ lines at a given time. Selection of pins as IRQ lines
is handled by IA55 (which is the IRQC block) which sits in between the
GPIO and GIC.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220707182314.66610-7-prabhakar.mahadev-lad.rj@bp.renesas.com