This merges the driver wrapper implementations to use the same
implementation both for hostapd and wpa_supplicant operations to avoid
code duplication.
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.
