irqchip/armada-370-xp: Fix ack/eoi breakage

When converting the driver to using handle_percpu_devid_irq,
we forgot to repaint the irq_eoi() callback into irq_ack(),
as handle_percpu_devid_fasteoi_ipi() was actually using EOI
really early in the handling. Yes this was a stupid idea.

Fix this by using the HW ack method as irq_ack().

Fixes: e52e73b7e9f7 ("irqchip/armada-370-xp: Make IPIs use handle_percpu_devid_irq()")
Reported-by: Steffen Trumtrar <[e-mail]>
Tested-by: Steffen Trumtrar <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>
Cc: Valentin Schneider <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]

drivers/irqchip/irq-armada-370-xp.c

···
 		ARMADA_370_XP_SW_TRIG_INT_OFFS);
 }
 
-static void armada_370_xp_ipi_eoi(struct irq_data *d)
+static void armada_370_xp_ipi_ack(struct irq_data *d)
 {
 	writel(~BIT(d->hwirq), per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
 }
 
 static struct irq_chip ipi_irqchip = {
 	.name		= "IPI",
+	.irq_ack	= armada_370_xp_ipi_ack,
 	.irq_mask	= armada_370_xp_ipi_mask,
 	.irq_unmask	= armada_370_xp_ipi_unmask,
-	.irq_eoi	= armada_370_xp_ipi_eoi,
 	.ipi_send_mask	= armada_370_xp_ipi_send_mask,
 };