vchiq_arm: Service callbacks must not fail

Service callbacks are not allowed to return an error. The internal callback
that delivers events and messages to user tasks does not enqueue them if
the service is closing, but this is not an error and should not be
reported as such.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

drivers/misc/vc04_services/interface/vchiq_arm/vchiq_arm.c

@@ -224,7 +224,7 @@ add_completion(VCHIQ_INSTANCE_T instance, VCHIQ_REASON_T reason,
 		} else if (instance->closing) {
 			vchiq_log_info(vchiq_arm_log_level,
 				"service_callback closing");
-			return VCHIQ_ERROR;
+			return VCHIQ_SUCCESS;
 		}
 		DEBUG_TRACE(SERVICE_CALLBACK_LINE);
 	}