iommu: dma-mapping: add dma mapper for io-pgtable-fast for 32 bit

io-pgtable-fast was implemented to achieve
better performance for IOMMU map/un-map. Add
DMA API support that goes through io-pgtable-fast
for 32 bit targets.

Change-Id: Ib46157cabd1f9b31903837bcc0dcaad87037cdb6
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
[pdaly@codeaurora.org: Included only changes to general iommu files]
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>