[9fans] centrino wireless driver

[Russ Cox <rsc@swtch.com>]

I wrote the bulk of a driver for the wireless card
found in most Intel laptops these days.  It's in
/n/sources/contrib/rsc/ipw2200.
It is *unfinished*, i.e. *not* in working condition.

I've done all the low-level card setup and framework
for issuing commands and sending and receiving
packets.

What's left is figuring out how to scan for a base
station, associate with it, and then the various
wireless packet header processing in the packet
send and receive.

Also, occasionally I see "fatal errors" coming from
the card.  They seem to be associated with getting
a lot of packets all at once, though there are plenty
of buffers in the receive ring when that happens.

I may or may not get back to finishing it, so I'm
putting it up in case someone else wants to play.

Russ