Kill off the static single net device and move to proper dynamic
registration (which we need with the new device model).
Break the (flawed) assumption that all network-layer protocols can use
ARP; such network-layer protocols (i.e. IPv4) must now register as an ARP
protocol using ARP_NET_PROTOCOL() and provide a single method for checking
the existence of a local network-layer address.
async_wait(), though we may wish to move this higher up the stack, and
consider making the block device model asynchronous. (There is only a
marginal cost for synchronous devices, since they can simply call
async_done() before returning; async_wait() will work seamlessly in this
situation).
Removed data_in_len and data_out_len from ata_command structure; the
lengths are implied by the sector count and the presence of the data_in
or data_out pointers.
Changed AoE code to use subcommands by default, and made aoe_issue()
nonblocking (with completion via async_wait()).
Cannot yet handle reads of more than two sectors
No retransmission
No way to find out a target's MAC address (this proof of concept uses
broadcasts)
These limitations shall not last long! :)
