refactor(ff-a): direct messaging

Some functions from `src/ffa/{hypervisor,spmc}.c` were missed in the
refactoring.
Move them to `src/ffa/{hypervisor,spmc}/direct_messaging.c`.

Change-Id: Ic0a238fe676c8aa77110f539ccf9cdb9638b85e9
Signed-off-by: Karl Meakin <karl.meakin@arm.com>
diff --git a/inc/hf/ffa.h b/inc/hf/ffa.h
index 1a33d6c..936e2eb 100644
--- a/inc/hf/ffa.h
+++ b/inc/hf/ffa.h
@@ -15,9 +15,4 @@
 void plat_ffa_set_tee_enabled(bool tee_enabled);
 void plat_ffa_init(struct mpool *ppool);
 
-bool plat_ffa_is_spmd_lp_id(ffa_id_t vm_id);
-
 void plat_save_ns_simd_context(struct vcpu *vcpu);
-
-bool plat_ffa_handle_framework_msg(struct ffa_value args,
-				   struct ffa_value *ret);
diff --git a/inc/hf/ffa/direct_messaging.h b/inc/hf/ffa/direct_messaging.h
index eb87da8..968a2e9 100644
--- a/inc/hf/ffa/direct_messaging.h
+++ b/inc/hf/ffa/direct_messaging.h
@@ -35,3 +35,8 @@
 
 void ffa_direct_msg_unwind_call_chain_ffa_direct_resp(
 	struct vcpu_locked current_locked, struct vcpu_locked next_locked);
+
+bool plat_ffa_handle_framework_msg(struct ffa_value args,
+				   struct ffa_value *ret);
+
+bool plat_ffa_is_spmd_lp_id(ffa_id_t vm_id);