lantiq_etop: remove unnecessary setting of skb->dev

skb->dev is being unnecessarily set before calling eth_type_trans.
eth_type_trans already sets skb->dev to the proper value, thus making this
unnecessary.

Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: David S. Miller <davem@davemloft.net>