Determine the network-layer packet type and fill it in for UNDI
clients.  This is required by some NBPs such as emBoot's winBoot/i.

This change requires refactoring the link-layer portions of the
gPXE netdevice API, so that it becomes possible to strip the
link-layer header without passing the packet up the network stack.

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.

Infiniband devices no longer block waiting for link-up in
register_ibdev().

Hermon driver needs to create an event queue and poll for link-up events.

Infiniband core needs to reread MAD parameters when link state changes.

IPoIB needs to cope with Infiniband link parameters being only partially
available at probe and open time.

Signed-off-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>

Arbel and Hermon cards both have multiple ports.  Add the
infrastructure required to register each port as a separate IB
device.  Don't yet register more than one port, since registration
will currently fail unless a valid link is detected.

Use ib_*_{set,get}_{drv,owner}data wrappers to access driver- and
owner-private data on Infiniband structures.

tracking down a bug that turned out to be a free_iob() used where I
needed a netdev_tx_complete().  This left the freed I/O buffer on the
net device's TX list, with bad, bad consequences later.

Also fixed the bug in question.