m68knommu: platform setup for 523x ColdFire parts

Switch to platform style configuration for 523x ColdFire parts.
Initial support is for the UARTs. DMA support moved to common code
for all ColdFire parts.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>