iommu/dma: Implement dma_{map,unmap}_resource()

With the new dma_{map,unmap}_resource() functions added to the DMA API
for the benefit of cases like slave DMA, add suitable implementations to
the arsenal of our generic layer. Since cache maintenance should not be
a concern, these can both be standalone callback implementations without
the need for arch code wrappers.

Git-Commit: 51f8cc9e818a9e6df376db7aeb5822d43e58cfb3
Git-Repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds


CC: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Change-Id: I72088ed5a4f946fcbd54be9533d5b5d0618a4e2a
Signed-off-by: Joerg Roedel <jroedel@suse.de>