staging: rtl8712: remove duplicate struct

struct ndis_wlan_bssid_ex is a doppelganger of struct wlan_bssid_ex,
and is used about a third as often.

Switch all instances to wlan_bssid_ex, and remove ndis_wlan_bssid_ex

This also gets rid of a use of typedef NDIS_802_11_RATES_EX

Signed-off-by: Joshua Clayton <stillcompiling@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>