ath9k: distinguish between device initialization and ath_softc init

We re-label the device driver initialization routines from the
ath_softc, the "Software Carrier" fillers. This should make it
clearer what each of these do.

Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>