e1000: Add support for the CE4100 reference platform

This patch adds support for the gigabit phys present on the CE4100 reference
platforms.

Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>