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.h b/aos/prime/input/joystick_input.h
index c44c5e2..ec97580 100644
--- a/aos/prime/input/joystick_input.h
+++ b/aos/prime/input/joystick_input.h
@@ -9,8 +9,8 @@
 // A class for handling joystick packet values.
 // It will call RunIteration each time a new packet is received.
 //
-// This class automatically handles updating ::aos::robot_state and logging (at
-// INFO) button edges.
+// This class automatically handles updating ::aos::joystick_state and logging
+// (at INFO) button edges.
 class JoystickInput {
  public:
   void Run();