tulip: fix hang in dmfe driver on sending of big packet

This patch fixes hang in dmfe driver on attempt of sending a big packet.
Without this patch the code stops the queue and never wakes it again.

Signed-off-by: Alexander V. Lukyanov <lav@netis.ru>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>