rt2x00dev isn't interested in the rt2x00leds_register() value
anyway. So lets make it return void to even prevent people from
assuming there is anybody interested in the returnvalue.
Signed-off-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Add kerneldoc for vendor request functions in rt2x00usb.
Add asynchroneous vendor request function in rt2x00usb.

With the availability of the asynchroneuous vendor request
we can now enable LED class support for rt2500usb and rt73usb.
Since LED handling is not important, it doesn't really matter
if a register call fails (This solution is better then no
LED class support at all).
Signed-off-by: NIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>