mlxsw: spectrum: Add the needed callbacks for mlxfw integration

The mlxfw module defines several needed callbacks in order to flash the
device's firmware. As the mlxfw module is shared between several different
drivers, those callbacks are the glue functionality that is responsible
for hardware interaction. Add those callbacks using the MCQI, MCC, MCDA
registers.

Signed-off-by: Yotam Gigi <yotamg@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>