Add ability for network devices to flag link up/down state to the
networking core.

Autobooting code will now wait for link-up before attempting DHCP.

IPoIB reflects the Infiniband link state as the network device link state
(which is not strictly correct; we also need a succesful IPoIB IPv4
broadcast group join), but is probably more informative.

via UNDI API and also by ifstat command; may be useful for debugging.

names.

Add "dev" pointer in struct net_device to tie network interfaces back to a
hardware device.

Force natural alignment of data types in __table() macros.  This seems to
prevent gcc from taking the unilateral decision to occasionally increase
their alignment (which screws up the table packing).

Call netdevice's poll() and transmit() methods only when device is open.

"boot" command to attempt booting from within the command shell, fall back
to shell if boot fails for any reason.

typical build will now include 880 bytes of PCI support code, compared to
2327 bytes in Etherboot 5.4.

(There is a slight cost of around 5 extra bytes per access to a
non-constant config space address; this should be an overall win.
Driver-specific accesses will usually be to constant addresses, for
which there is no additional cost.)

Yes, you really can do it in 65 bytes.