virtual_oss.8: Remove CPU performance example

See also:	https://github.com/freebsd/virtual_oss/issues/2
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week

usr.sbin/virtual_oss/virtual_oss/virtual_oss.8

@@ -23,7 +23,7 @@
 .\" SUCH DAMAGE.
 .\"
 .\"
-.Dd September 3, 2024
+.Dd April 17, 2026
 .Dt VIRTUAL_OSS 8
 .Os
 .Sh NAME
@@ -325,17 +325,6 @@ server:
 virtual_oss -S -b 16 -C 2 -c 2 -r 48000 -s 4ms \\
 	-f /dev/sndio/default -d dsp
 .Ed
-.Pp
-How to set intel based CPUs in performance mode:
-.Bd -literal -offset indent
-sysctl -aN | fgrep dev.hwpstate | fgrep epp | \
-while read OID
-do
-sysctl ${OID}=0
-done
-
-sysctl kern.sched.preempt_thresh=224
-.Ed
 .Sh NOTES
 All character devices are created using the 0666 mode which gives
 everyone in the system access.