net: sgi: ioc3-eth: don't abuse dma_direct_* calls

dma_direct_ is a low-level API that must never be used by drivers
directly.  Switch to use the proper DMA API instead.

Fixes: ed870f6a ("net: sgi: ioc3-eth: use dma-direct for dma allocations")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>