m68k: Remove empty #ifdef/#ifndef block

Whatever code this was guarding has been removed so remove the guards
too.

Signed-off-by: Chris Packham <judge.packham@gmail.com>

Move architecture-specific includes to arch/$ARCH/include/asm

This helps to clean up the include/ directory so that it only contains
non-architecture-specific headers and also matches Linux's directory
layout which many U-Boot developers are already familiar with.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>