Implement minimal PSCI for secondary VMs to manage their vCPUs.

Bug: 132422393
Change-Id: I44643ec9eec722dfe0332b7ffefadcdd8dd98985
diff --git a/inc/hf/api.h b/inc/hf/api.h
index 259d59e..a0151c0 100644
--- a/inc/hf/api.h
+++ b/inc/hf/api.h
@@ -40,7 +40,9 @@
 
 struct vcpu *api_preempt(struct vcpu *current);
 struct vcpu *api_wait_for_interrupt(struct vcpu *current);
+struct vcpu *api_vcpu_off(struct vcpu *current);
 struct vcpu *api_abort(struct vcpu *current);
+struct vcpu *api_wake_up(struct vcpu *current, struct vcpu *target_vcpu);
 
 int64_t api_interrupt_enable(uint32_t intid, bool enable, struct vcpu *current);
 uint32_t api_interrupt_get(struct vcpu *current);