genirq/irq_sim: add an extended irq_sim initializer

genirq/irq_sim: add an extended irq_sim initializer

Currently users of the interrupt simulator don't have any way of being
notified about interrupts from the simulated domain being requested or
released. This causes a problem for one of the users - the GPIO
simulator - which is unable to lock the pins as interrupts.

Define a structure containing callbacks to be executed on various
irq_sim-related events (for now: irq request and release) and provide an
extended function for creating simulated interrupt domains that takes it
and a pointer to custom user data (to be passed to said callbacks) as
arguments.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240624093934.17089-2-brgl@bgdev.pl
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>