RDMA/addr: Handle ethernet neighbour updates during route resolution

The iWARP connection manager uses the ib_addr services to do route
resolution (neighbour discovery in the IP world).  The ib_addr
netevent callback routine, however, currently only acts on InfiniBand
neighbour updates.  It needs to act on ethernet neighbour updates as
well.

This patch just removes filtering on device type altogether and will
trigger on any neighour updates where the nud_type is valid.  This
simplifies the code some.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>