netdrv: don't truncate VLAN TCI with VLAN stripping

The vlan_hwaccel_{rx,receive_skb} functions expect the full TCI field
for priority mappings, don't truncate the upper 4 bits.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>