mesa: rename _mesa_free_errors_data

Use the _mesa_init_XXX / _mesa_destroy_XXX pattern to clearly associate
the 2 functions.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5789>
3 files changed