feat(psci): add psci_do_manage_extensions API

Adding a new API under PSCI library,for managing all the architectural
features, required during power off or suspend cases.

Change-Id: I1659560daa43b9344dd0cc0d9b311129b4e9a9c7
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
diff --git a/include/lib/psci/psci_lib.h b/include/lib/psci/psci_lib.h
index 4b244ec..c50f8cb 100644
--- a/include/lib/psci/psci_lib.h
+++ b/include/lib/psci/psci_lib.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2022, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2023, Arm Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -94,6 +94,7 @@
 bool psci_is_last_on_cpu_safe(void);
 bool psci_are_all_cpus_on_safe(void);
 void psci_pwrdown_cpu(unsigned int power_level);
+void psci_do_manage_extensions(void);
 
 #endif /* __ASSEMBLER__ */