ies code setup the archdata.dma_data before that assignment was
done - effectively overwriting the dma_data with NULL.

Fix this up by moving the iSeries setup of dma_data into a
pci_dma_dev_setup callback.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
ÌYR