Introduce typedef for vCPU index.

Change-Id: I51194706edb86811487f2a22b3bda5405e605b5e
diff --git a/src/arch/aarch64/hypervisor/psci_handler.c b/src/arch/aarch64/hypervisor/psci_handler.c
index 76e4798..2736814 100644
--- a/src/arch/aarch64/hypervisor/psci_handler.c
+++ b/src/arch/aarch64/hypervisor/psci_handler.c
@@ -24,6 +24,7 @@
 #include "hf/cpu.h"
 #include "hf/dlog.h"
 #include "hf/panic.h"
+#include "hf/spci.h"
 #include "hf/vm.h"
 
 #include "psci.h"
@@ -227,7 +228,7 @@
  * Convert a PSCI CPU / affinity ID for a secondary VM to the corresponding vCPU
  * index.
  */
-uint32_t vcpu_id_to_index(uint64_t vcpu_id)
+spci_vcpu_index_t vcpu_id_to_index(uint64_t vcpu_id)
 {
 	/* For now we use indices as IDs for the purposes of PSCI. */
 	return vcpu_id;
@@ -282,7 +283,8 @@
 		uint32_t lowest_affinity_level = arg1;
 		struct vm *vm = vcpu->vm;
 		struct vcpu_locked target_vcpu;
-		uint32_t target_vcpu_index = vcpu_id_to_index(target_affinity);
+		spci_vcpu_index_t target_vcpu_index =
+			vcpu_id_to_index(target_affinity);
 
 		if (lowest_affinity_level != 0) {
 			/* Affinity levels greater than 0 not supported. */
@@ -327,7 +329,8 @@
 		uint64_t target_cpu = arg0;
 		ipaddr_t entry_point_address = ipa_init(arg1);
 		uint64_t context_id = arg2;
-		uint32_t target_vcpu_index = vcpu_id_to_index(target_cpu);
+		spci_vcpu_index_t target_vcpu_index =
+			vcpu_id_to_index(target_cpu);
 		struct vm *vm = vcpu->vm;
 		struct vcpu *target_vcpu;