dp83640: don't hold spinlock while calling netif_rx_ni

We should not hold a spinlock while pushing the skb into the networking
stack, so move the call to netif_rx_ni out of the critical region to where
we have dropped the spinlock.

Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
Signed-off-by: David S. Miller <davem@davemloft.net>