{net,ib}/mlx5: Don't disable local loopback multicast traffic when needed

There are systems platform information management interfaces (such as
HOST2BMC) for which we cannot disable local loopback multicast traffic.

Separate disable_local_lb_mc and disable_local_lb_uc capability bits so
driver will not disable multicast loopback traffic if not supported.
(It is expected that Firmware will not set disable_local_lb_mc if
HOST2BMC is running for example.)

Function mlx5_nic_vport_update_local_lb will do best effort to
disable/enable UC/MC loopback traffic and return success only in case it
succeeded to changed all allowed by Firmware.

Adapt mlx5_ib and mlx5e to support the new cap bits.

Fixes: 2c43c5a0 ("net/mlx5e: Enable local loopback in loopback selftest")
Fixes: c85023e1 ("IB/mlx5: Add raw ethernet local loopback support")
Fixes: bded747b

 ("net/mlx5: Add raw ethernet local loopback firmware command")
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Cc: kernel-team@fb.com
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>