mlxsw: spectrum: Reserved field in mbox profile shouldn't be set

There is no need to set some of the fields within 'mbox_config_profile',
since they are reserved and capability mask should be set to zero.

Signed-off-by: Tal Bar <talb@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>