staging: r8188eu: remove odm_interface

After previous cleanups the file odm_interface.c is emtpy now
and the header odm_interface.h just contains an unused typedef.
Remove both files.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20211229205108.26373-13-straube.linux@gmail.com


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