Remove mallocs in realtime trajectory code

Modifications to GetDrivetrainConfig for y2024 (which uses the constants
flatbuffer as a source of the drivetrain config) make it
non-realtime-safe.

Change-Id: Iad160acf3cf09d0feacb4498d03884f1065acc94
Signed-off-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>
diff --git a/y2019/control_loops/drivetrain/localizer_test.cc b/y2019/control_loops/drivetrain/localizer_test.cc
index 7f0b13d..7c33579 100644
--- a/y2019/control_loops/drivetrain/localizer_test.cc
+++ b/y2019/control_loops/drivetrain/localizer_test.cc
@@ -173,7 +173,7 @@
           spline_goal_buffer(fbb.Release());
 
       frc971::control_loops::drivetrain::Trajectory trajectory(
-          spline_goal_buffer.message(), dt_config_);
+          spline_goal_buffer.message(), &dt_config_);
       trajectory.Plan();
 
       flatbuffers::FlatBufferBuilder traj_fbb;