arm64: Pass the correct coherent flag for iommu operations

The memory to be mapped by the smmu needs to be uncached
since the bus is non-coherent. Pass coherent flag as false
to make sure that the memory is marked as uncached.

CRs-Fixed: 786121
Change-Id: Ie2849b1e1ec901e60e89706519cbd89d278e0b3e
Signed-off-by: Neeti Desai <neetid@codeaurora.org>
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>