staging: rtl8723bs: remove obsolete wext support

cfg80211 has been fully implemented so
remove all wext and wext private handlers and their
registration.

Now wext userspace calls can be managed via
cfg80211 wext compatibility.

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/61c4bb20bbb6ce30e4ddd01aa73de3f686a99445.1629727333.git.fabioaiuto83@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>