ath9k_hw: Fix selfgen chainmask for 9565

Self generated MCI messages is configured to use chain 1. As
ar9565 is 1x1 solution, It can not use Chain 1. Hence fix
Chain 1 for ar9462 alone. Not doing so, could affect WLAN
connectivity in ar9565 as LNA sharing is not informed by BT.

Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>