SPMD: [EXP] Hook up support for PSCI usage from the secure world

This patch delegates invocation of PSCI calls from the secure world to the SMC
handler registered by the SPMD.

Signed-off-by: Achin Gupta <achin.gupta@arm.com>
diff --git a/services/std_svc/spmd/spmd_main.c b/services/std_svc/spmd/spmd_main.c
index 2e96803..251c05d 100644
--- a/services/std_svc/spmd/spmd_main.c
+++ b/services/std_svc/spmd/spmd_main.c
@@ -274,6 +274,9 @@
 	/* Reuse PSCI affinity states to mark this SPMC context as off */
 	spm_core_context[plat_my_core_pos()].state = AFF_STATE_OFF;
 
+	/* Register power management hooks with PSCI */
+	psci_register_spd_pm_hook(&spmd_pm);
+
 	INFO("SPM core setup done.\n");
 
 	/* Register init function for deferred init.  */