CFR: rfkill facility

Hi,

I've spend quite bit of time to get the RF kill switch handling correct 
while working on iwn(4). During that I have noticed that almost every 
driver has its own quirks to get things done and that there is no way to 
get the state exposed to the user.

An interface for that might address those issues. I had some spare time and  
put a few things together:
http://techwires.net/~bschmidt/patches/freebsd/rfkill/

With that and just a few modifications to a driver, e.g. for iwn(4)
http://techwires.net/~bschmidt/patches/freebsd/iwn/iwn_rfkill.diff
we can get a more desirable outcome.

maja:~# rfkill
  RFID Device           Type             Hard   Soft
     1 iwn0             WLAN             no     no

-- 
Bernhard