The separate header file is not needed since none of the driver wrappers
include it anymore. Move the WLAN_STA_* definitions back to be together
with struct sta_info definition.
Instead of getting this via hostapd.h, include it as the first
non-system header file in all source code files in the same way as
used in all other files.
This updates management frame protection to use the assocition ping process
from the latest draft (D6.0) to protect against unauthenticated
authenticate or (re)associate frames dropping association.
