spelling fix; from miod

Work in progress support for the SGI Indigo, Indigo 2 and Indy systems
(IP20, IP22, IP24) in 64-bit mode, adapated from NetBSD. Currently limited
to headless operation, input and video drivers will get ported soon.

Should work on all R4000, R4440 and R5000 based systems. L2 cache on R5000SC
Indy not supported yet (coming soon), R4600 not supported yet either (coming
soon as well).

Tested to boot multiuser on: Indigo2 R4000SC, Indy R4000PC, Indy R4000SC,
Indy R5000SC, Indigo2 R4400SC. There are still glitches in the Ethernet driver
which are being looked at.

Expansion support is limited to the GIO E++ board; GIO boards with PCI-GIO
bridges not ported yet due to the lack of hardware, and this kind of driver
does not port blindly.

Most of this work comes from NetBSD, polishing and integration work, as well
as putting as many ``R4x00 in 64-bit mode'' erratas as necessary, by yours
truly.

More work is coming, as well as trying to get some easy way to boot install
kernels (as older PROM can only boot ECOFF binaries, which won't do for the
kernel).

typos from Tom Cosgrove;

Tom: I did not commit a couple of your changes.

i did not include some punctuation fixes (full stops, etc.)
mnemorable -> mnemonic: i decided memorable was probably better
instrunctions -> instruction: i kept the plural

Remove the advertising clause in the UCB license which Berkeley
rescinded 22 July 1999. Proofed by myself and Theo.

branches: 1.4.14;
Adaption to new bus.h from NetBSD. Various driver has been updated to
NetBSD 961107 state. Other has not, partly because sometimes the bus.h
changes was coupled with other changes.

$OpenBSD RCSIDs

z8530 reorganization from gwr (which i think isn't nearly as machine
independent or correct as he thinks it is)

branches: 1.1.1;
Initial revision