m68knommu: platform setup for 520x ColdFire parts

Switch to platform style configuration for 520x 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>