There is a performance issue when the number of VSIs are not multiple
of 8. This is caused due to the max children limitation per node(8) in
9 layer topology. The BW credits are shared evenly among the children
by default. Assume one node has 8 children and the other has 1.
The parent of these nodes share the BW credit equally among them.
Apparently this causes a problem for the first node which has 8 children.
The 9th VM get more BW credits than the first 8 VMs.

Example:

1) With 8 VM's:
for x in 0 1 2 3 4 5 6 7;
do taskset -c ${x} netperf -P0 -H 172.68.169.125 &  sleep .1 ; done

tx_queue_0_packets: 23283027
tx_queue_1_packets: 23292289
tx_queue_2_packets: 23276136
tx_queue_3_packets: 23279828
tx_queue_4_packets: 23279828
tx_queue_5_packets: 23279333
tx_queue_6_packets: 23277745
tx_queue_7_packets: 23279950
tx_queue_8_packets: 0

2) With 9 VM's:
for x in 0 1 2 3 4 5 6 7 8;
do taskset -c ${x} netperf -P0 -H 172.68.169.125 &  sleep .1 ; done

tx_queue_0_packets: 24163396
tx_queue_1_packets: 24164623
tx_queue_2_packets: 24163188
tx_queue_3_packets: 24163701
tx_queue_4_packets: 24163683
tx_queue_5_packets: 24164668
tx_queue_6_packets: 23327200
tx_queue_7_packets: 24163853
tx_queue_8_packets: 91101417

So on average queue 8 statistics show that 3.7 times more packets were
send there than to the other queues.

The FW starting with version 3.20, has increased the max number of
children per node by reducing the number of layers from 9 to 5. Reflect
this on driver side.
Signed-off-by: Raj Victor <victor.raj@intel.com>
Co-developed-by: Michal Wilczynski <michal.wilczynski@intel.com>
Signed-off-by: Michal Wilczynski <michal.wilczynski@intel.com>
Co-developed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Signed-off-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
Tested-by: Pucha Himasekhar Reddy <himasekharx.reddy.pucha@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>