net: dsa: felix: allow flooding for all traffic classes

Right now it can be seen that the VSC9959 (Felix) switch will not flood
frames if they have a VLAN tag with a PCP of 1-7 (nonzero).

It turns out that Felix is quite different from its cousin, Ocelot, in
that frame flooding can be allowed/denied per traffic class. Where
Ocelot has 1 instance of the ANA_FLOODING register, Felix has 8.

The approach that this driver is going to take is "thanks, but no
thanks". We have no use case of limiting the flooding domain based on
traffic class, so we just want to allow packets to be flooded, no matter
what traffic class they have.

So we copy the line of code from ocelot.c which does the one-shot
initialization of the flooding PGIDs, and we add it to felix.c as well -
except replicated 8 times.

Signed-off-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>