Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Start each of the license/copyright comments with /*-, minor shuffle of lines

Add a driver for the AMD AM79c873 10/100 PHY. By some strange coincidence,
this PHY and the Davicom DM9101 have exactly the same register definitions.
One of them is probably a clone of the other. I'm not sure which.

This is needed for the Davicom DM9102 10/100 PCI ethernet driver which
will be committed shortly.