proper sizing of kmem_arena on different ports

PR port-i386/45946: Kernel locks up in VMEM system

branches: 1.16.4; 1.16.8;
Remove clause 3 (UCB advertising clause) from the University of Utah
copyright. Confirmed by Mike Hibler, mike at cs.utah.edu - thanks!
Also, merge UCB and Utah copyright texts back into one, as they
originally were.

Extra verification by snj@.

branches: 1.15.2; 1.15.4;
Switch NetBSD/news68k to using 8KB/page in kernel.
It slightly improves performance on NWS-1750D (MC68030 25MHz):
http://mail-index.NetBSD.org/port-m68k/2009/12/08/msg000204.html

MI m68k/pmap_motorola.c and other sources can handle both 4KB/8KB pages
(amiga and atari have used 8KB pages for many years) and there is
no binary compatibility issue on it.
(kernel modules might be affected but 5.99.29 was just two days ago)

branches: 1.14.2; 1.14.4;
Refactoring MD segment related definitions on m68k ports:
- move macro SEGSHIFT, NBSEG, and SEGOFSET from <machine/param.h>
to <m68k/pmap_motorola.h> where they should belong
- also simplify NBSEG macro for both 020/030 and 040/060 cases
- also move m68k_trunc_seg(), m68k_round_seg(), and m68k_seg_offset()
(that use SEGOFSET) from <m68k/param.h> to <m68k/pmap_motorola.h>
- add comments about each segment size value used on pmap_motorola
implementation
- add TIA_SIZE, TIA_SHIFT, TIB_SIZE, and TIB_SHIFT macro which can be
used for ste/pte index sizes
- use proper vaddr_t cast instead of unsigned for SEGOFSET/PGOFSET macro

Tested on atari, hp300, and news68k.

Fix wrong NBSEG values for all hp300 pmap derived m68k ports.
They were incorrect since 1997 on amiga and atari, and since 2002
on other ports, but fortunately they don't look so fatal.

Anyway, these values will be moved into <m68k/pmap_motorola.h> soon
since they are quite pmap implementation dependent.

branches: 1.12.10;
Remove COMPAT_HPUX.

branches: 1.11.20; 1.11.26; 1.11.32;
Merge #ifdef _KERNEL stuff into one place.

branches: 1.10.2;
Implement generic softintr(9) support for news68k.
Mostly taken from mvme68k.

Use _NEWS68K_FOO_H_ rather than _MACHNE_FOO_H_.

branches: 1.8.16;
Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22364, verified by myself.

branches: 1.7.2;
Remove __P().

merge pmap.h for all 4k-page motorola-MMU (or compatible) m68k platforms.

branches: 1.5.8;
use _KERNEL_OPT

branches: 1.4.2;
Change UPAGES from 3 to 2. (sync with hp300)

branches: 1.3.2;
Reduce NKMEMPAGES_MIN_DEFAULT.

Update for the NKMEMPAGES changes.

branches: 1.1.2;
Initial import of news68k port.