util: fix fossilize_db compile error

Observed in Fuchsia build (with -Wwrite-strings):

error: passing 'const char[10]' to parameter of type 'char *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30334>

src/util/fossilize_db.c

@@ -98,7 +98,7 @@ check_files_opened_successfully(FILE *file, FILE *db_idx)
 
 static bool
 create_foz_db_filenames(const char *cache_path,
-                        char *name,
+                        const char *name,
                         char **filename,
                         char **idx_filename)
 {