net: designware: Export various functions/struct to allow subclassing

net: designware: Export various functions/struct to allow subclassing

To allow other DM drivers to subclass the designware driver various
functions and structures need to be exported. Export these.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Signed-off-by: Romain Perier <romain.perier@collabora.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>