ata/pata_arasan_cf: fill dma chan->private from pdata->dma_priv

ata/pata_arasan_cf: fill dma chan->private from pdata->dma_priv

Some DMA controllers (eg: drivers/dma/dw_dmac*) allow platform specific
configuration for dma transfers. User drivers need to set chan->private field
of channel with pointer to configuration data. This patch takes dma_priv data
from platform data and passes it to chan->private_data, in order to pass
platform specific configuration to DMAC controller.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>