vmount: rate-limit the update of the outputs

This avoids a busy-loop if the input is listening for vehicle commands and
the output publishes vehicle commands.

src/drivers/vmount/vmount.cpp

@@ -222,6 +222,7 @@ static int vmount_thread_main(int argc, char *argv[])
 	g_thread_data = &thread_data;
 
 	int last_active = 0;
+	hrt_abstime last_output_update = 0;
 
 	while (!thread_should_exit) {
 
@@ -342,6 +343,10 @@ static int vmount_thread_main(int argc, char *argv[])
 				}
 			}
 
+			hrt_abstime now = hrt_absolute_time();
+			if (now - last_output_update > 10000) { // rate-limit the update of outputs
+				last_output_update = now;
+
 				//update output
 				int ret = thread_data.output_obj->update(control_data);
 
@@ -351,6 +356,7 @@ static int vmount_thread_main(int argc, char *argv[])
 				}
 
 				thread_data.output_obj->publish();
+			}
 
 		} else {
 			//wait for parameter changes. We still need to wake up regularily to check for thread exit requests