P2PS: Add channel policy to PD Request

P2PS: Add channel policy to PD Request

Add operating channel selection and channel list processing similar to
that done when building GO Negotiation Request, i.e., consider the
currently used channels, configured channels, etc.

P2PS introduces a flow where a responder needs to provide channel data
without being previously aware of the current constraints, i.e., the
channels currently in use by other interfaces. To handle this, extend
the get_group_capability() callback to also handle channel selection
aspects of group capabilities.

In case there is an active P2P GO that is going to be used for the P2PS
PD, force its current operating frequency in the PD attributes.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>