iommu/exynos: Add support for IOMMU_DOMAIN_DMA domain type

This patch adds support for DMA domain type. Such domain have DMA cookie
prepared and can be used by generic DMA-IOMMU glue layer.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>