Add power management support in the SPD

This patch implements a set of handlers in the SPD which are called by
the PSCI runtime service upon receiving a power management
operation. These handlers in turn pass control to the Secure Payload
image if required before returning control to PSCI. This ensures that
the Secure Payload has complete visibility of all power transitions in
the system and can prepare accordingly.

Change-Id: I2d1dba5629b7cf2d53999d39fe807dfcf3f62fe2
diff --git a/services/psci/psci_main.c b/services/psci/psci_main.c
index 67f189d..ca3a5a0 100644
--- a/services/psci/psci_main.c
+++ b/services/psci/psci_main.c
@@ -178,7 +178,7 @@
 /* Unimplemented */
 unsigned int psci_migrate_info_type(void)
 {
-	return PSCI_TOS_NOT_PRESENT;
+	return PSCI_TOS_NOT_PRESENT_MP;
 }
 
 unsigned long psci_migrate_info_up_cpu(void)