staging: r8188eu: remove GetHalDefVarHandler from struct hal_ops

Remove GetHalDefVarHandler from struct hal_ops and remove its wrapper
rtw_hal_get_def_var(). Call GetHalDefVar8188EUsb() directly instead.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210929192657.9569-3-straube.linux@gmail.com


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