P2P: Cancel action frame offchan wait after recv GO Neg Conf

The missing call to scan_action_done() may keep us off-channel for 250
ms following sending GO Negotiation Response. In case the operating
channel is different from this channel and we're GO, a race could lead
to start beaconing while off-channel. This could potentially cause the
Beacon frames to go out on incorrect channel with some drivers.

Signed-hostap: Eyal Shapira <eyal@wizery.com>