iommu/tegra-smmu: Fix iova->phys translation

IOVA might not be always 4KB aligned. So tegra_smmu_iova_to_phys
function needs to add on the lower 12-bit offset from input iova.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20200911071643.17212-3-nicoleotsuka@gmail.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>