msm: iommu: use sg_dma_address() in iommu_map_range()

Ion carveout and content protect buffers do not have
a struct page and thus sg_phys() cannot be used on them.
Try sg_dma_address() first and if it returns 0 then
use sg_phys().

Change-Id: I95ccb8f5a3c86cd09ecf2a2737c260f4996059ac
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>