mlxsw: spectrum: Upper-bound supported FW version

During initialization the driver checks whether the flashed FW image
suits its requirements by checking that it's sufficiently new.
However, there's only a weak backward compatibility scheme that is
actually guaranteed by the FW, so driver must also upper bound the
version to prevent compatibility issues between current driver and some
possible future fw.

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