staging: r8188eu: remove some structure definitions from wlan_bssdef.h

ndis_802_11_ai_reqfi, ndis_802_11_ai_resfi, ndis_802_11_assoc_info,
ndis_802_11_remove_key, ndis_802_11_auth_req, ndis_802_11_status_ind,
ndis_802_11_auth_evt, ndis_802_11_test, pmkid_candidate, ndis_802_11_pmkid_list,
ndis_802_11_auth_encrypt and ndis_802_11_cap structures are not used.

Signed-off-by: Ivan Safonov <insafonov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>