m68knommu: move ColdFire DMA register addresses to per-cpu headers

The base addresses of the ColdFire DMA unit registers belong with
all the other address definitions in the per-cpu headers. The current
definitions assume they are relative to an MBAR register. Not all
ColdFire CPUs have an MBAR register. A clean address define can only
be acheived in the per-cpu headers along with all the other chips
peripheral base addresses.

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