P2P: Limit join-a-group scans based on SSID from invitation

P2P: Limit join-a-group scans based on SSID from invitation

If we already know the SSID of the P2P group we are trying to join, use
that SSID to limit scan responses and BSS selection since we do not
really look for any other network in this case. In addition, this can
fix cases where the peer has just changed its SSID (e.g., started a new
group) and there may be multiple BSS entries for the same BSSID.

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