net: fec: correct queue selection

The old implementation extracted VLAN TCI info from the payload
before the VLAN tag has been pushed in the payload.

Another problem was that the VLAN TCI was extracted even if the
packet did not have VLAN protocol header.

This resulted in invalid VLAN TCI and as a consequence a random
queue was computed.

This patch fixes the above issues and use the VLAN TCI from the
skb if it is present or VLAN TCI from payload if present. If no
VLAN header is present queue 0 is selected.

Fixes: 52c4a1a8

 ("net: fec: add ndo_select_queue to fix TX bandwidth fluctuations")
Signed-off-by: Radu Bulie <radu-andrei.bulie@nxp.com>
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>