Linux ath9k.
The ath9k ar9002_hw_init_cal() isn't entirely clear about what
is supposed to be called for what chipsets, so I'm ignoring the
rest of it and just porting the AR9285 init cal path as-is and
leaving the rest alone. Subsequent commits may also tidy up the
Merlin (AR9285) and other chipset support.
Obtained from: Linux ath9k
