Remove mostly obsolete hint to disable LAPIC timers.

It is partially covered by new code and partially by new CPUs.

PR:		195016
Submitted by:	tobias.rehbein@web.de
MFC after:	1 week


git-svn-id: svn+ssh://svn.freebsd.org/base/head@274532 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f