P2P: Fix P2P Group Formation timeout registration (use parent iface)

Commit 361cdf34009c7407ddf22dee6f5e6ce82e81bcae extended the use of
group formation timeout for the way handshake, but the registration was
done on the group_interface while the cancellation was done on the
parent interface. Fix the registration to set the eloop timeout on
parent to address potential issues when using a separate group
interface.

Signed-hostap: Nirav Shah <nirav.j2.shah@intel.com>

wpa_supplicant/p2p_supplicant.c

@@ -3743,7 +3743,7 @@ void wpas_p2p_wps_success(struct wpa_supplicant *wpa_s, const u8 *peer_addr,
 		 */
 		eloop_register_timeout(P2P_MAX_INITIAL_CONN_WAIT, 0,
 				       wpas_p2p_group_formation_timeout,
-				       wpa_s, NULL);
+				       wpa_s->parent, NULL);
 	}
 	if (wpa_s->global->p2p)
 		p2p_wps_success_cb(wpa_s->global->p2p, peer_addr);