iommu: dma-mapping-fast: Avoid pci memory regions

Certain memory regions are reserved by pci devices. When an endpoint
makes an access to these regions, the access is routed to the appropriate
location with the pci complex, and does not pass through the iommu into
the greater system. Therefore these address cannot be used for dma.

Change-Id: I1e909e4c0fbcadd53576b27a57cc49ed131cf328
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>