mlxsw: spectrum: Update the supported firmware to version 13.1702.6

This new firmware contains:
        - Support for new types of cables
        - Support for flashing future firmware without reboot
        - Support for Router ARP BC and UC traps

Signed-off-by: Nir Dotan <nird@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>