dp83640: Fix NOHZ local_softirq_pending 08 warning

Similar problem as in 481a8199 ("can:
fix NOHZ local_softirq_pending 08 warning"). This fix replaces
netif_rx() with netif_rx_ni() which has to be used from
process/softirq context.

Signed-off-by: Manfred Rudigier <manfred.rudigier@omicron.at>
Signed-off-by: David S. Miller <davem@davemloft.net>