mlxsw: spectrum: Update the supported firmware to version 13.1620.192

This new firmware contains:
	- Support for auto-neg disable mode

Signed-off-by: Tal Bar <talb@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>