Add duty cycle to CANPosition logging

We keep seeing falcons do things that are different from what we
commanded, so log what the falcon is actually doing.

Signed-off-by: Ravago Jones <ravagojones@gmail.com>
Change-Id: Idfeeaf5cf51223f815e9d360d479b64229d33a55
diff --git a/y2023/control_loops/superstructure/superstructure_position.fbs b/y2023/control_loops/superstructure/superstructure_position.fbs
index 83ca2b6..b09e077 100644
--- a/y2023/control_loops/superstructure/superstructure_position.fbs
+++ b/y2023/control_loops/superstructure/superstructure_position.fbs
@@ -38,6 +38,9 @@
 
   // Raw position
   position:float (id: 5);
+
+  // Nominal range is -1 to 1, but can be -2 to +2
+  duty_cycle:float (id: 6);
 }
 
 table Position {