aux/trace: Guard triggers behind __normal_user

Reviewed-by: Eric Engestrom <eric@igalia.com>
Cc: mesa-stable
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27381>

src/gallium/auxiliary/driver_trace/tr_dump.c

@@ -284,7 +284,7 @@ trace_dump_trace_begin(void)
       atexit(trace_dump_trace_close);
 
       const char *trigger = debug_get_option("GALLIUM_TRACE_TRIGGER", NULL);
-      if (trigger) {
+      if (trigger && __normal_user()) {
          trigger_filename = strdup(trigger);
          trigger_active = false;
       } else