mlxsw: spectrum: Add Spectrum-2 ASIC support for new port types and speeds

Add Spectrum-2 ASIC support for the following new port types and speeds:
  * 50Gbps 1-lane
  * 100Gbps 2-lanes
  * 200Gbps 4-lanes

Signed-off-by: Shalom Toledo <shalomt@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>