IB/mlx4: Initialize hop_limit when creating address handle

Hop limit value wasn't copied from attributes  when ah was created.
This may influence packets for unconnected services to get dropped in
routers when endpoints are not in the same subnet.

Fixes: fa417f7b ("IB/mlx4: Add support for IBoE")
Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>