ath6kl: Set optimal listen intvl,bmiss,scan params while going to wow suspend

* In order to save the target power in WOW suspend state,
  configure the best optimal values for the below parameters,
     - listen interval.
     - beacon miss interval.
     - scan parameters.

  Default values for above attributes are reverted in
  wow resume operation.

* The default listen interval is set before the host issue
  connect request.

* New function is added to configure beacon miss count.

kvalo: minor changes to fix open parenthesis alignment

Signed-off-by: Raja Mani <rmani@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>