staging: rtl8188eu: remove dummy wext handlers

Remove the wext handlers that link to an empty dummy function.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20210529121346.8422-2-martin@kaiser.cx


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