staging: r8188eu: remove rtw_set_scan_mode()

Function rtw_set_scan_mode() is not used, remove it.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210922200420.9693-23-straube.linux@gmail.com


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