irqchip/apple-aic: Drop unused ipi_hwirq field

This field was never used, remove it.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20220108140118.3378937-1-maz@kernel.org

drivers/irqchip/irq-apple-aic.c

@@ -178,7 +178,6 @@ struct aic_irq_chip {
 	struct irq_domain *hw_domain;
 	struct irq_domain *ipi_domain;
 	int nr_hw;
-	int ipi_hwirq;
 };
 
 static DEFINE_PER_CPU(uint32_t, aic_fiq_unmasked);