CLOCK_VECTOR and define it as 254, not 255. Vector 255 is already
in use as the AP wakeup vector on the HP rx2600.
This needs to be made more dynamic. The likelyhood of vector 254
being in use is pretty small, but we already have code to assign
vectors to IPIs (see sal.c) and it's preobably better to have a
centralized "vector manager" that hands out vectors based on
some imput (like priority).
handleclock itself is trivial.
While here, replace (itc_frequency+hz/2)/hz with itm_reload for
consistency. There's now a single place where we determine the
ITM reload value.
not work on any real hardware (or fully work on any simulator). Much more
needs to happen before this is actually functional but its nice to see
the FreeBSD copyright message appear in the ia64 simulator.
