ath9k: defer btcoex scheme update

As btcoex scheme updation might sleep, remove the function call
from tasklet context and queue it up as a separate work.

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