feat(psci): add a helper function to ensure that non-boot PEs are offline

Introduce a helper function that ensures that non-boot PEs are offline.
This function will be used by DRTM implementation to ensure that system
is running with only single PE.

Signed-off-by: Manish V Badarkhe <manish.badarkhe@arm.com>
Signed-off-by: Lucian Paul-Trifu <lucian.paultrifu@gmail.com>
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I521ebefa49297026b02554629b1710a232148e01
diff --git a/lib/psci/psci_private.h b/lib/psci/psci_private.h
index 72bd6bd..61bd966 100644
--- a/lib/psci/psci_private.h
+++ b/lib/psci/psci_private.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2020, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2013-2022, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -47,6 +47,9 @@
  */
 #define PSCI_MAX_CPUS_INDEX	0xFFFFU
 
+/* Invalid parent */
+#define PSCI_PARENT_NODE_INVALID	0xFFFFFFFFU
+
 /*
  * Helper functions to get/set the fields of PSCI per-cpu data.
  */