Introduce typedef for [v]CPU IDs.

Change-Id: I99988988d8ac57c688c5fd52f072357202255f18
diff --git a/src/cpu.c b/src/cpu.c
index 802235a..9b44d97 100644
--- a/src/cpu.c
+++ b/src/cpu.c
@@ -50,11 +50,11 @@
 	sl_init(&c->lock);
 }
 
-void cpu_module_init(const uint64_t *cpu_ids, size_t count)
+void cpu_module_init(const cpu_id_t *cpu_ids, size_t count)
 {
 	uint32_t i;
 	uint32_t j;
-	uint64_t boot_cpu_id = cpus[0].id;
+	cpu_id_t boot_cpu_id = cpus[0].id;
 	bool found_boot_cpu = false;
 
 	cpu_count = count;
@@ -68,7 +68,7 @@
 	j = cpu_count;
 	for (i = 0; i < cpu_count; ++i) {
 		struct cpu *c;
-		uint64_t id = cpu_ids[i];
+		cpu_id_t id = cpu_ids[i];
 
 		if (found_boot_cpu || id != boot_cpu_id) {
 			c = &cpus[--j];
@@ -132,7 +132,7 @@
 /**
  * Searches for a CPU based on its id.
  */
-struct cpu *cpu_find(uint64_t id)
+struct cpu *cpu_find(cpu_id_t id)
 {
 	size_t i;