hostapd: fix P2P group information processing vulnerability

hostapd: fix P2P group information processing vulnerability

A vulnerability was discovered in how wpa_supplicant processing P2P
(Wi-Fi Direct) group information from active group owners.
This issue was discovered by fuzz testing of wpa_supplicant by Google's
OSS-Fuzz.

https://w1.fi/security/2020-2/wpa_supplicant-p2p-group-info-processing-vulnerability.txt

Signed-off-by: Daniel Golle <[email protected]>
[added the missing patch]
Signed-off-by: Petr Štetiar <[email protected]>
(cherry-picked from commit 7c8c4f1be648aff9f1072ee27a2cc8f6a4a788ef)