P2P: Avoid multi-channel scans when they are not needed

P2P: Avoid multi-channel scans when they are not needed

If the driver does not support multi-channel concurrency and a virtual
interface that shares the same radio with the current interface is
operating there may not be need to scan other channels apart from the
current operating channel on the other virtual interface. Filter out
other channels in case we are trying to find a connection for a station
interface when we are not configured to prefer station connection and a
concurrent operation is already in process.

Signed-hostap: Jouni Malinen <j@w1.fi>