Hide switch to primary logic.

This should not be called directly by arch code.

Change-Id: I8a83179d66565e571ff4a4b254020af4a06a937b
diff --git a/inc/hf/api.h b/inc/hf/api.h
index d598ffc..42c371b 100644
--- a/inc/hf/api.h
+++ b/inc/hf/api.h
@@ -3,16 +3,15 @@
 #include "hf/cpu.h"
 #include "hf/vm.h"
 
-struct vcpu *api_switch_to_primary(size_t primary_retval,
-				   enum vcpu_state secondary_state);
-
 int32_t api_vm_get_count(void);
 int32_t api_vcpu_get_count(uint32_t vm_id);
 int32_t api_vcpu_run(uint32_t vm_id, uint32_t vcpu_idx, struct vcpu **next);
-struct vcpu *api_wait_for_interrupt(void);
 int32_t api_vm_configure(ipaddr_t send, ipaddr_t recv);
 
 int32_t api_rpc_request(uint32_t vm_id, size_t size);
 int32_t api_rpc_read_request(bool block, struct vcpu **next);
 int32_t api_rpc_reply(size_t size, bool ack, struct vcpu **next);
 int32_t api_rpc_ack(void);
+
+struct vcpu *api_wait_for_interrupt(void);
+struct vcpu *api_yield(void);