iwlwifi: mvm: change active-to-powersave transition time for BPS

The requirement for TX/RX active to powersave transition time for
the Balanced Power Save (BPS) scheme changed. Change the driver
accordingly and set transition time to 100 msec.

Signed-off-by: Alexander Bondar <alexander.bondar@intel.com>
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>