ath9k: Handle 2-ANT AR9565 in MCI reset

The value programmed in the BTCOEX control register
is different for each chip. This patch adds support
for 2-ANT, 1-ANT solutions based on AR9565.

Signed-off-by: Sujith Manoharan <c_manoha@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>