powerpc/pmac: Fix PowerSurge SMP IPI allocation

The code for setting up the IPIs for SMP PowerSurge marchines bitrot,
it needs to properly map the HW interrupt number
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powermac/smp.c

@@ -408,7 +408,7 @@ static void __init smp_psurge_setup_cpu(int cpu_nr)
 	/* reset the entry point so if we get another intr we won't
 	 * try to startup again */
 	out_be32(psurge_start, 0x100);
-	if (setup_irq(30, &psurge_irqaction))
+	if (setup_irq(irq_create_mapping(NULL, 30), &psurge_irqaction))
 		printk(KERN_ERR "Couldn't get primary IPI interrupt");
 }