ath5k: Misc fixes/cleanups

*Handle MIB interrupts and pass low level stats to mac80211
*Add Power On Self Test function
*Update to match recent dumps
*Let RF2425 attach so we can further test it
*Remove unused files regdom.c and regdom.h

base.c
Changes-licensed-under: 3-clause-BSD

rest
Changes-licensed-under: ISC

Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>