scripts: add tracepoint-update to the list of ignores files

The new program for removing unused tracepoints is not ignored as it
should. Add it to the local .gitignore.

Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/20251029120709.24669-1-brgl@bgdev.pl
Fixes: e30f8e61e251 ("tracing: Add a tracepoint verification check at build time")
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>