net: e1000: Convert to driver model

Update this driver to support driver model.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Tested-on: Apalis T30 2GB on Apalis Evaluation Board