update the information about enabled vs not

With the roboRIO, we get different information about whether motors are
enabled (and some about sensors too), so the system for propagating it
around to everything needs to change.

Change-Id: I7e5f9591eeac1fdfe57b271333c3827431fbef01
diff --git a/aos/prime/input/joystick_input.cc b/aos/prime/input/joystick_input.cc
index 08441c2..ca4a033 100644
--- a/aos/prime/input/joystick_input.cc
+++ b/aos/prime/input/joystick_input.cc
@@ -12,11 +12,11 @@
 void JoystickInput::Run() {
   driver_station::Data data;
   while (true) {
-    robot_state.FetchAnother();
+    joystick_state.FetchAnother();
 
-    LOG_STRUCT(DEBUG, "sending", *robot_state);
+    LOG_STRUCT(DEBUG, "sending", *joystick_state);
 
-    data.Update(*robot_state);
+    data.Update(*joystick_state);
 
     {
       using driver_station::JoystickFeature;