This was not documented properly and was not really used nor would it be
suitable to be used in generic way as it was implemented. It is better
to just remove the parameter since there does not seem to be any
reasonable use for it.
This commit merges the driver_ops structures and implementations from
hostapd/driver*.[ch] into src/drivers. This is only an initial step and
there is room for number of cleanups to share code between the hostapd
and wpa_supplicant parts of the wrappers to avoid unnecessary source
code duplication.
