RDMA/mlx5: Allow creating RAW ethernet QP with loopback support

Expose two new flags:
MLX5_QP_FLAG_TIR_ALLOW_SELF_LB_UC
MLX5_QP_FLAG_TIR_ALLOW_SELF_LB_MC

Those flags can be used at creation time in order to allow a QP
to be able to receive loopback traffic (unicast and multicast).
We store the state in the QP to be used on the destroy path
to indicate with which flags the QP was created with.

Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>