iommu: io-pgtable-fast: Use the DMA APIs for cache cleaning

When doing cache maintenance for the page tables, we currently
use the architecture specific dmac_clean_range() function, which
is no longer available. Instead of using architecture specific,
functions for cache maintenance, use the generic DMA APIs for
cleaning the caches.

Change-Id: I086d12da8205c0a5fbc65efc4ec6534b1ee6ab39
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>