Add more diagnostic output for failure.

Add more diagnostic output for failure.

s/1518/ETHER_MAX_LEN

Some style changes, add some braces, mostly residual from having
a lot of debug hooks added while working on this driver.

Bring in a plethora of changes from NetBSD:

	revision 1.58
	date: 2001/03/08 11:07:08;  author: ichiro;  state: Exp;  lines: +17 -1
	it wait until busy flag disappears.
	it was able to prevent some cards with late initializing faling in wi_reset().

	revision 1.41
	date: 2000/10/13 19:15:08;  author: jonathan;  state: Exp;  lines: +4 -2
	Fix wi_intr() to avoid touching card registers during insert/remove  events,
	when sharing an interrupt with other devices:
	check sc->sc_enabled,  and drop the interrupt if its' off.

	revision 1.30
	date: 2000/08/18 04:11:48;  author: jhawk;  state: Exp;  lines: +4 -4
	Copy wi_{dst,src}_addr from struct wi_frame into faked-up ether_header
	instead of addr1 and addr2. THis means that tcpdump -e will show the
	correct MAC address for communications with access points instead of showing
	the BSSID.

	In the future there should be 802.11 support for bpf/libpcap/tcpdump,
	but that is aways down the road.