pasemi_mac: Print warning when not attaching to a PHY

pasemi_mac: Print warning when not attaching to a PHY

Print a warning on the console when not connecting to a phy for an interface.
It turns out to be a pretty common problem when someone gets the MDIO info
wrong in their device tree, resulting in the macs running at a fixed 1Gbit FD.

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