irqchip/i8259: Fix shutdown order by moving syscore_ops registration

When using cpufreq on Loongson 2F MIPS platform, "poweroff"
command gets frequently stuck in syscore_shutdown(). The reason is
that i8259A_shutdown() gets called before cpufreq_suspend(), and if we
have pending work then irq_work_sync() in cpufreq_dbs_governor_stop()
gets stuck forever as we have all interrupts masked already.

irq-i8259 is registering syscore_ops using device_initcall(),
while cpufreq uses core_initcall(). Fix the shutdown order simply
by registering the irq syscore_ops during the early IRQ init instead
of using a separate initcall at later stage.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/irq-i8259.c

@@ -225,14 +225,6 @@ static struct syscore_ops i8259_syscore_ops = {
 	.shutdown = i8259A_shutdown,
 };
 
-static int __init i8259A_init_sysfs(void)
-{
-	register_syscore_ops(&i8259_syscore_ops);
-	return 0;
-}
-
-device_initcall(i8259A_init_sysfs);
-
 static void init_8259A(int auto_eoi)
 {
 	unsigned long flags;
@@ -332,6 +324,7 @@ struct irq_domain * __init __init_i8259_irqs(struct device_node *node)
 		panic("Failed to add i8259 IRQ domain");
 
 	setup_irq(I8259A_IRQ_BASE + PIC_CASCADE_IR, &irq2);
+	register_syscore_ops(&i8259_syscore_ops);
 	return domain;
 }