wpa_supplicant: Fix updating GO beacons on WFD subelements change
When WFD Subelements are set, the IE in the Beacon frames of already
existing groups are not updated. This patch fixes this issue by setting
beacon_update to be 1 on WFD IE update.
Signed-hostap: Andrei Otcheretianski <andrei.otcheretianski@intel.com>