pseries dma: DMA window params added to PHB and DT population changed

pseries dma: DMA window params added to PHB and DT population changed

Previously the only PCI bus supported was the emulated PCI bus with
fixed DMA window with start at 0 and size 1GB. As we are going to support
PCI pass through which DMA window properties are set by the host
kernel, we have to support DMA windows with parameters other than default.

This patch adds:

1. DMA window properties to sPAPRPHBState: LIOBN (bus id), start,
size of the window.

2. An additional function spapr_dma_dt() to populate DMA window
properties in the device tree which simply accepts all the parameters
and does not try to guess what kind of IOMMU is given to it.
The original spapr_dma_dt() is renamed to spapr_tcet_dma_dt().

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>