FreeBSD has no good way of finding the Hertz value. ELF notes don't
work, you can't find it in a function and even asm/params.h does
not have it. Lucky for us, it is always 100.
Based upon Debian patch patch sysinfo_kfreebsd_hertz by Petr Salinger
Bug-Debian: http://bugs.debian.org/460331
Caution, 460331 has lots of overlapping bugs all around the Hertz
problem across many arches.