long_mpc set qp_tol to 1e-3

NOTE: 1e-2 was breaking selfdrive/controls/tests/test_following_distance.py for 0 m/s,
rest works fine though

selfdrive/controls/lib/longitudinal_mpc_lib/long_mpc.py

@@ -181,7 +181,7 @@ def gen_long_mpc_solver():
   # More iterations take too much time and less lead to inaccurate convergence in
   # some situations. Ideally we would run just 1 iteration to ensure fixed runtime.
   ocp.solver_options.qp_solver_iter_max = 10
-  ocp.solver_options.qp_tol = 1e-2
+  ocp.solver_options.qp_tol = 1e-3
 
   # set prediction horizon
   ocp.solver_options.tf = Tf