Preparatory change to remove irq_remapping_get_irq_domain().
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-25-dwmw2@infradead.org