x86/apic/uv: Fix the hotplug notifier

The notifier is missing the CPU_DOWN_FAILED transition. That leaves the
heartbeat disabled when CPU_DOWN_PREPARE fails.

It also does not handle the FROZEN transition variants. That might not be an
issue for UV, but it's inconsistent.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dimitri Sivanich <sivanich@sgi.com>

arch/x86/kernel/apic/x2apic_uv_x.c

@@ -792,7 +792,8 @@ static int uv_scir_cpu_notify(struct notifier_block *self, unsigned long action,
 {
 	long cpu = (long)hcpu;
 
-	switch (action) {
+	switch (action & ~CPU_TASKS_FROZEN) {
+	case CPU_DOWN_FAILED:
 	case CPU_ONLINE:
 		uv_heartbeat_enable(cpu);
 		break;