Add support for treating unknown PHYs as generic PHYs.
When bringing up u-boot on new boards, PHY support sometimes gets
neglected. Most PHYs don't really need any special support,
though. By adding a generic entry that always matches if nothing
else does, we can provide support for "unsupported" PHYs for the
tsec.
The generic PHY driver supports most PHYs, including gigabit.
Signed-off-by: David Updegraff <dave@cray.com> Signed-off-by: Andy Fleming <afleming@freescale.com>