Pull the following amiga's pmap changes to atari:
arch/amiga/amiga/amiga_init.c 1.95-1.97, 1.100-1.102
arch/amiga/amiga/pmap.c 1.123, 1.124, 1.126-1.131, 1.142, 1.145
arch/amiga/amiga/pmap_bootstrap.c 1.1, 1.2, 1.3, 1.4
arch/amiga/conf/files.amiga 1.137
arch/amiga/include/pcb.h 1.16
arch/amiga/include/pmap.h 1.44
arch/amiga/include/pte.h 1.19
arch/amiga/include/vmparam.h 1.35

- change kernel address space layout (i.e. move Sysmap to the end of KVA)
  to match other m68k ports, which should be done on yamt-km merge
- rework pmap_zero_page(), pmap_copy_page() and some more other functions
  to make them compatible with m68k/pmap_motorola.c
- move pmap_bootstrap() into a separate file to allow using either
  the atari pmap.c or the m68k common pmap_motorola.c
- use common m68k include files, pcb.h, pmap_motorola.h, and pte_motorola.h
- misc style and cosmetic changes

Most merge work is done by Tuomo Makinen, and
miscellaneous fixes and cleanups are done by me.

Tested on Falcon with both 68030 and 68060 by Tuomo, and
also tested on TT030 by David Ross on port-atari.

Should be pulled up to netbsd-4 (it requires at least Sysmap changes)
and netbsd-5.

(tsutsui)