staging: rtl8723bs: MapCharToHexDigit() is not used

The function MapCharToHexDigit() is not used anywhere, remove it.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230310083449.23775-2-straube.linux@gmail.com


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