define KERN_TIMEOUT_STATS and incr KERN_MAXID on OpenBSD

`KERN_TIMEOUT_STATS` has been defined in [sys/sysctl.h (1.194)](https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sys/sys/sysctl.h?rev=1.194&content-type=text/x-cvsweb-markup)