ath5k: Update registers and SREV ids v2

 * Update registers
 * Update SREV values and add some PHY srevs
 * Prepare ath5k.h for newer radios etc

 Thanks to Atheros 's HAL source we now know for sure how many parts we have
 and what their SREV values are. We also have some updates on registers. Prepare
 ath5k for some major updates ;-)

 My previous mail had 2 more patches following (git log misusage), sorry for double
 posting ;-(

Changes-Licensed-under: ISC
Signed-Off-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>