P2P: Fix cross connection allowed parser to use correct field

The previous version had a bug that could result in NULL pointer
dereference if the P2P IE included Manageability attribute, but no
Capability attribute.

src/p2p/p2p_parse.c

@@ -661,7 +661,7 @@ int p2p_get_cross_connect_disallowed(const struct wpabuf *p2p_ie)
 	if (!msg.manageability)
 		return 0;
 
-	return !(msg.capability[0] & P2P_MAN_CROSS_CONNECTIION_PERMITTED);
+	return !(msg.manageability[0] & P2P_MAN_CROSS_CONNECTIION_PERMITTED);
 }