net: dsa: bcm_sf2: Configure traffic classes to queue mapping

By default, all traffic goes to queue 0, re-configure the traffic
classes to quality of service mapping such that priority X maps to queue
X, where X is from 0 through 7.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>