PA Semi PWRficient Ethernet driver

Driver for the PA Semi PWRficient on-chip Ethernet (1/10G)

Basic enablement, will be complemented with performance enhancements
over time. PHY support will be added as well.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>