ath9k_hw: fix BT RF performance

When software rfkill is triggered, before put the chip in reset
state, give LNA and SPDT control to BT to make sure BT can have
good RF performance.

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