m68knommu: platform setup for 5407 ColdFire parts

Switch to platform style configuration for 5407 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>