From: Chris Bajumpaa <cbajumpa@or8.net>

This patch fixes a problem with the TSC failing on via686a/KX133
motherboards either reverting to using the pit or deadlocking the machine
alltogether under heavy load.  (Specifically Abit KA7/KA7-100).

Message from the log:
Dec 18 18:20:37 grinder kernel: Losing too many ticks!
Dec 18 18:20:37 grinder kernel: TSC cannot be used as a timesource. (Are
you running with SpeedStep?)
Dec 18 18:20:37 grinder kernel: Falling back to a sane timesource.

The snippet of code that was missing from timer_tsc.c comes from
timer_pit.c.