m68knommu: clean up ColdFire 532x CPU timer setup

The newer ColdFire 532x family of CPU's uses the old timer, but has a
newer interrupt controller. It doesn't need the special timer setup
that was required when using the older interrupt controller. Remove the
dead timer irq and level setting code, and define the hard coded vector.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>