Existing user space applications provide only IBoE L3 address
attributes to the kernel when they issue a modify QP modify.  To work
with them and let such apps (plus kernel consumers which don't use the
RDMA-CM) keep working transparently under the IBoE GID IP addressing
changes, add an Eth L2 address resolution helper.
Signed-off-by: Moni Shoua <monis@mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>