m68knommu: platform code merge for 68000 core cpus

This patch merges all 68000 core cpus into one directory.
There is a lot of common code in the 68328, 68EZ328 and 68VZ328 directories.

This will also facilitate easy development of support for original stand
alone MC68000 CPU machines.

Signed-off-by: Luis Alves <ljalvs@gmail.com>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>