dpaa_eth: change device used

Change device used for DMA mapping to the MAC device that is an
of_device, with proper DMA ops. Using this device for the netdevice
should also address the issue with DSA scenarios that need the
netdevice to be backed by an of_device.

Signed-off-by: Madalin Bucur <madalin.bucur@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>