FF-A: FFA_MSG_SEND_DIRECT_REQ with invalid IDs

A call to FFA_MSG_SEND_DIRECT_REQ with invalid VM IDs should return
error with code FFA_INVALID_PARAMETERS.

Change-Id: Iedfa173b37857f6f0b7297b6be012c51c51b169a
Signed-off-by: J-Alves <joao.alves@arm.com>
diff --git a/src/api.c b/src/api.c
index cce9cf9..2667283 100644
--- a/src/api.c
+++ b/src/api.c
@@ -1666,7 +1666,7 @@
 
 	if (!arch_other_world_is_direct_request_valid(current, sender_vm_id,
 						      receiver_vm_id)) {
-		return ffa_error(FFA_NOT_SUPPORTED);
+		return ffa_error(FFA_INVALID_PARAMETERS);
 	}
 
 	receiver_vm = vm_find(receiver_vm_id);
@@ -1802,7 +1802,7 @@
 
 	if (!arch_other_world_is_direct_response_valid(current, sender_vm_id,
 						       receiver_vm_id)) {
-		return ffa_error(FFA_NOT_SUPPORTED);
+		return ffa_error(FFA_INVALID_PARAMETERS);
 	}
 
 	current_locked = vcpu_lock(current);