sungem: remove unnecessary setting of skb->dev

skb->dev is being unnecessarily set by the driver's skb alloc routine (which is
called in init and during rx).  It is already being set to the proper value when
eth_type_trans is called on packet receive, and the skb->dev is not referenced
anywhere else in the code.

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