iwlwifi: mvm: clear csa countdown when AP is stopped

iwlwifi: mvm: clear csa countdown when AP is stopped

commit e9cb0327b26dd7ba43a3b7a05b4b62219decf42d upstream.

The csa_countdown flag was not cleared when the AP is stopped.
As a result, if the AP was stopped after csa_countdown had started,
all the folowing channel switch commands would fail.
Fix that by clearing the csa_countdown flag when the AP is stopped.

Signed-off-by: Avraham Stern <avraham.stern@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>