pinctrl: nomadik: Make gpio irqchip immutable

This makes the Nomadik GPIO irqchip immutable.

Tested on the Samsung Galaxy SIII mini GT-I8190.

Cc: Marc Zyngier <maz@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220917203036.167607-2-linus.walleij@linaro.org


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>