net/mlx5e: Support FEC settings for 200G per lane link modes

Add support to show and config FEC by ethtool for 200G/lane link
modes. The RS encoding setting is mapped, and can be overridden to
FEC_RS_544_514_INTERLEAVED_QUAD for these modes.

Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Shahar Shitrit <shshitrit@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>