m68knommu: move old ColdFire timers init from CPU init to timers code

The original ColdFire timer interrupt setup is used by most of the users
of the original ColdFire timer code. But the code is currently duplicated
in each of the ColdFire CPU specific init files. Move it to the timers
code that it is really part of. It is strait forward to make it conditional
on also having the original interrupt engine that it needs.

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