bgmac: omit the fcs

Do not include the frame check sequence when adding the skb to
netif_receive_skb(). This causes problems when this interface was
bridged to a wifi ap and a big package should be forwarded from this
Ethernet driver through a bride to the wifi client.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: David S. Miller <davem@davemloft.net>