Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Update ipw to work with the new net80211 stack, plus other driver improvements.

- Add proper scanning support rather than letting the firmware grab the first
access point
- Overhaul state changes
- Use macros for locking and provide _locked() versions of some functions
- Increase debugging output
- Use a callout rather than the old watchdog interface
- Improve style, function names and defines
- Add WPA (TKIP) support

Based heavily on a patchset provided by Sam Leffler.

sync w/ iwi:
o fix locking
o use firmware(9)
o cosmetic

Initial import of ipw, iwi, ral and ural drivers:

ipw - Intel PRO/Wireless 2100
iwi - Intel PRO/Wireless 2200BG/2225BG/2915ABG
ral - Ralink Technology RT2500
ural - Ralink Technology RT2500USB

Approved by: silby (mentor)