From: Tim Schmielau <tim@physik3.uni-rostock.de>

Fixes the problem wherein nanosleep() is sleeping for the wrong duration.

When starting out with timer_jiffies=0, the timer cascade is (unneccessarily)
triggered on the first timer interrupt, incrementing all the higher indices.
When starting with any other initial jiffies value, we miss that and end up
with all higher indices being off by one.