net: davinci_emac:Fix translation logic for buffer descriptor

net: davinci_emac:Fix translation logic for buffer descriptor

With recent changes to the driver(switch to new cpdma layer),
the support for buffer descriptor address translation logic
is broken. This affects platforms where the physical address of
the descriptors as seen by the DMA engine is different from the
physical address.

Original Patch adding translation logic support:
Commit: ad021ae8862209864dc8ebd3b7d3a55ce84b9ea2

Signed-off-by: Sriramakrishnan A G <srk@ti.com>
Tested-By: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>