iwlwifi: mvm: Add power management support for P2P DCM

If two clients are active while each one is alone on its channel,
and the applicable flags are set, power management should be enabled.
This condition is referred to as Different Channel Mode (DCM).
Up to now, in DCM power management was supported only on BSS.
This patch adds support for P2P power management in DCM as well.

Signed-off-by: Avri Altman <avri.altman@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>