util/u_trace: Fix iteration over config_control

Fixes: e1811af75d
("util/perf: add options to enable/disable tracepoints")

Signed-off-by: Danylo Piliaiev <dpiliaiev@igalia.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16781>

src/util/perf/u_trace.py

@@ -316,6 +316,7 @@ static const struct debug_control config_control[] = {
 %    for toggle_name in TRACEPOINTS_TOGGLES.keys():
    { "${toggle_name}", ${trace_toggle_name.upper()}_${toggle_name.upper()}, },
 %    endfor
+   { NULL, 0, },
 };
 uint64_t ${trace_toggle_name} = 0;