powerpc/pseries: Disable VPNH feature

This feature triggers nasty races in the scheduler between the
rebuilding of the topology and the load balancing code, causing
the machine to hang.

Disable it for now until the races are fixed.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/mm/numa.c

@@ -1516,7 +1516,8 @@ int start_topology_update(void)
 {
 	int rc = 0;
 
-	if (firmware_has_feature(FW_FEATURE_VPHN) &&
+	/* Disabled until races with load balancing are fixed */
+	if (0 && firmware_has_feature(FW_FEATURE_VPHN) &&
 	    get_lppaca()->shared_proc) {
 		vphn_enabled = 1;
 		setup_cpu_associativity_change_counters();