Add interfaces to allow the creation and destruction of a
LAG demux flow table.

It is a special flow table used during LAG for redirecting
non user-mode packets from PF0 to PF1 root ft, if a packet was
received on phys port two.
Signed-off-by: NAviv Heller <avivh@mellanox.com>
Reviewed-by: NMaor Gottlieb <maorg@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>
Signed-off-by: NLeon Romanovsky <leon@kernel.org>