Names used in libconfig's configuration files only allow alphanumerics,
underscores, dashes and asterisks. Freedreno device names, used as names
in fdperf.cfg, can also contain other characters, currently spaces and
plus characters. Not accounting for those makes it impossible to store
fdperf configuration across separate runs.
Once the Freedreno device name is retrieved, it's now sanitized for use
in fdperf.cfg. Unsupported characters are converted to underscores.
Signed-off-by: Zan Dobersek <zdobersek@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31577>