m68knommu: move UART addressing to part specific includes

The ColdFire UART base addresses varies between the different ColdFire
family members. Instead of keeping the base addresses with the UART
definitions keep them with the other addresses definitions for each
ColdFire part.

The motivation for this move is so that when we add new ColdFire
part definitions, they are all in a single file (and we shouldn't
normally need to modify the UART definitions in mcfuart.h at all).

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