Add a driver that implements the (IPoIB) IP-over-InfiniBand protocol.
This is a network device driver of type ARPHRD_INFINIBAND (and
addr_len INFINIBAND_ALEN bytes).

The ARP/ND implementation for this driver is not completely
straightforward, because InfiniBand requires an additional path lookup
be performed (through an IB-specific mechanism) after a remote
hardware address has been resolved.  We are very open to suggestions
of a better way to handle this than the current implementation.

Although IB has a special multicast group join mode intended to
support IP multicast routing (non member join), no means to identify
different multicast styles has yet been determined, so all joins by
the driver are currently full member joins.  We are looking for
guidance in how to solve this.

The IPoIB protocol/encapsulation is described in the Internet-Drafts
  http://www.ietf.org/internet-drafts/draft-ietf-ipoib-architecture-04.txt
  http://www.ietf.org/internet-drafts/draft-ietf-ipoib-ip-over-infiniband-08.txtSigned-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>