powerpc/pseries: Increase cpu die timeout

In testing SMT disable, we have been regularly seeing the following
message:

Querying DEAD? cpu %i (%i) shows %i

This indicates the current delay in pseries_cpu_die where we wait
for the specified CPU to die, is insufficient. Usually, this does
not cause a problem, but we've seen this result in BUG_ON's going
off in the timer code when we try to migrate the timers off the
dead cpu while a timer is still running. Increasing this delay,
as is done in this patch, seems to resolve this issue.
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/pseries/hotplug-cpu.c

@@ -193,12 +193,12 @@ static void pseries_cpu_die(unsigned int cpu)
 
 	if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
 		cpu_status = 1;
-		for (tries = 0; tries < 1000; tries++) {
+		for (tries = 0; tries < 5000; tries++) {
 			if (get_cpu_current_state(cpu) == CPU_STATE_INACTIVE) {
 				cpu_status = 0;
 				break;
 			}
-			cpu_relax();
+			msleep(1);
 		}
 	} else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) {