ath9k_hw: Fix async fifo for AR9287

Async fifo is now enabled only for versions 1.3 and above.
Enable it in the appropriate place, in the reset routine,
instead of process_ini().

Signed-off-by: Sujith <Sujith.Manoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>