P2P: Fix p2p_cancel processing during group formation

P2P: Fix p2p_cancel processing during group formation

The wpa_s->p2p_in_provisioning flag did not get cleared in some cases
where p2p_cancel command is used to stop group formation. This can result
in some operations (like p2p_find) failing afterwards. Fix this by using
wpas_group_formation_completed() when processing p2p_cancel for a group
that has not yet completed group formation.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>