net: dsa: felix: qos classified based on pcp

Set the default QoS Classification based on PCP and DEI of vlan tag,
after that, frames can be Classified to different Qos based on PCP tag.
If there is no vlan tag or vlan ignored, use port default Qos.

Signed-off-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>