arm: Move ipi_teardown() to a CONFIG_HOTPLUG_CPU section

ipi_teardown() is only used when CONFIG_HOTPLUG_CPU is enabled.
Move the function to a location guarded by this config option.
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm/kernel/smp.c

@@ -85,7 +85,6 @@ static int nr_ipi __read_mostly = NR_IPI;
 static struct irq_desc *ipi_desc[MAX_IPI] __read_mostly;
 
 static void ipi_setup(int cpu);
-static void ipi_teardown(int cpu);
 
 static DECLARE_COMPLETION(cpu_running);
 
@@ -236,6 +235,17 @@ int platform_can_hotplug_cpu(unsigned int cpu)
 	return cpu != 0;
 }
 
+static void ipi_teardown(int cpu)
+{
+	int i;
+
+	if (WARN_ON_ONCE(!ipi_irq_base))
+		return;
+
+	for (i = 0; i < nr_ipi; i++)
+		disable_percpu_irq(ipi_irq_base + i);
+}
+
 /*
  * __cpu_disable runs on the processor to be shutdown.
  */
@@ -707,17 +717,6 @@ static void ipi_setup(int cpu)
 		enable_percpu_irq(ipi_irq_base + i, 0);
 }
 
-static void ipi_teardown(int cpu)
-{
-	int i;
-
-	if (WARN_ON_ONCE(!ipi_irq_base))
-		return;
-
-	for (i = 0; i < nr_ipi; i++)
-		disable_percpu_irq(ipi_irq_base + i);
-}
-
 void __init set_smp_ipi_range(int ipi_base, int n)
 {
 	int i;