Add pico/imu reset counters to IMU status

Attempt to track when the pico and/or IMU reset based on when the data
counter and pico timestamps jump unexpectedly.

Notes:
* Not actually tested on robot.
* It would be good to get these values exposed on a webpage.

Change-Id: I5ac89ce9493017bc58a741a302b5cdc856fbdcf6
Signed-off-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>
diff --git a/frc971/imu_reader/imu_failures.fbs b/frc971/imu_reader/imu_failures.fbs
index e6d9d85..50764a2 100644
--- a/frc971/imu_reader/imu_failures.fbs
+++ b/frc971/imu_reader/imu_failures.fbs
@@ -13,4 +13,12 @@
   // Total number of messages dropped for any other conditions that can fault
   // the zeroer (e.g., diagnostic failures in the IMU).
   other_zeroing_faults:uint (id: 3);
+  // These are the counts for the number of times that we think the pico and imu
+  // have reset. Note that when the pico resets both of these should increment.
+  probable_pico_reset_count:uint (id: 4);
+  probable_imu_reset_count:uint (id: 5);
+  // This counter is used for things that look like resets (i.e., a large gap in
+  // IMU readings) but where the IMU data counter and pico timestamp offsets
+  // still look correct.
+  unassignable_reset_count:uint (id: 6);
 }