e1000: warn if this driver is used for e1000e devices

We're already starting to see reports from users still
using e1000 where they should be using e1000e now that this is
actually possible. Just to prevent some of this thrash, add
a big warning on load on these devices that people should
switch to e1000e.

Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Acked-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>