mlxsw: cmd: Introduce FID-offset flooding tables

Packets destined to offloaded netdevs will be classified to FIDs in the
device and flooded in case of BUM.

The flooding table used is of type FID-offset, which allows one to
create different flooding domains for different FIDs and specify the
offset in the flooding table for each FID (not necessarily equal to FID
or VID).

Add support for this flooding table type, by exposing the configuration
of the number of tables from this type and their size.

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