r8169: fix DMA being used after buffer free if WoL is enabled

r8169: fix DMA being used after buffer free if WoL is enabled

commit f658b90977d2e79822a558e48116e059a7e75dec upstream.

IOMMU errors have been reported if WoL is enabled and interface is
brought down. It turned out that the network chip triggers DMA
transfers after the DMA buffers have been freed. For WoL to work we
need to leave rx enabled, therefore simply stop the chip from being
a DMA busmaster.

Fixes: 567ca57faa62 ("r8169: add rtl8169_up")
Tested-by: Paul Blazejowski <paulb@blazebox.homeip.net>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>