While you can build multiplatform kernels for machines with classic
m68k processors, you cannot mix support for classic m68k and coldfire
processors. To avoid such hybrid kernels, introduce CONFIG_M68KCLASSIC
as an antipole for CONFIG_COLDFIRE, and make all specific processor
support depend on one of them.
All classic m68k machine support also needs to depend on this.

The defaults (CONFIG_M68KCLASSIC if MMU, CONFIG_COLDFIRE if !MMU) are
chosen such to make most of the existing configs build and work.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>