net/mlx5: E-Switch, Optimize HW steering tables in switchdev mode

Under switchdev mode we insert an eswitch miss rule causing any
unmatched traffic to be sent towards the PF vport. This miss rule can
be optimized if we break it to two, one case is for multicast traffic and
the other for unicast.

Breaking the miss rule into two (unicast and multicast) allows the firmware
to program the hardware in a more efficient way.

Using ConncetX-5 Ex with IXIA and testpmd (which use IB representors):

IXIA -> NIC -> PF -> IB representor -> NIC -> VF:
    - Without this optimization: 9.2 MPPS.
    - With this optimization: 18 MPPS.

VF -> NIC -> IB representor-> PF -> NIC -> IXIA:
    - Without this optimization: 17 MPPS.
    - With this optimization: 23.4 MPPS.

Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>