Commit  7d7355f5 ("sh_eth: Ensure proper ordering of descriptor active
bit write/read") did the right thing  but used too "heavy" barriers while
there were already "lighter" DMA barriers exactly  for this case...
Signed-off-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>