As reported by Aaro this patch causes network problems on
MIPS Loongson platform. Therefore revert it.

Fixes: f072218c ("r8169: remove not needed call to dma_sync_single_for_device")
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Reported-by: NAaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>