Everyone is away right now, so I'm going to use this
opportunity to slip in a somewhat contentious change:

See PR54549.

There are three different kinds of network drivers
that can be used with io-pkt:

1) io-net binary drivers, that are run with the
shim, and get the device name enX

2) ported bsd drivers, which use their bsd device
names, such as fxpX for speedo, and wmX for i82544

3) native io-pkt drivers, which currently use the bsd 
names, which creates confusion as to which driver is 
actually running.

Given that we currently allow different device
names for the same hardware (eg #1 vs #2) it
would seem to be reasonable to extend this 
naming difference convention to #2 vs #3.

So a few commits later ...

Native speedo driver now has device name spX which
means that a simple ifconfig tells you which of 3 
possible drivers is running on 82557/82558/82559 nic:

en0:  io-net binary
sp0:  io-pkt native
fxp0: bsd ported


And native i82544 driver now has device name prX
which means that a simple ifconfig tells you
which of 3 possible drivers is running:

en0:   io-net binary
pr0:    io-pkt native
wm0:  bsd ported