net/mlx5: Disable devlink reload for lag devices

Devlink reload can't be allowed on lag devices since reloading one lag
device will cause traffic on the bond to get stucked.
Users who wish to reload a lag device, need to remove the device from
the bond, and only then reload it.

Fixes: 4383cfcc ("net/mlx5: Add devlink reload")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>