The DMA API generally relies on a struct device to work properly, and
only barely works without one for legacy reasons.  Pass the easily
available struct device from the platform_device to remedy this.

Note that smc911x apparently is a PIO chip with an external DMA
handshake, and we probably use the wrong device here.  But at least
it matches the mapping side, which apparently works or at least
worked in the not too distant past.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>