Implement the map_pages() and unmap_pages() callback for the AMD IOMMU
driver to allow calls from iommu core to map and unmap multiple pages.
Also deprecate map/unmap callbacks.

Finally gatherer is not updated by iommu_v1_unmap_pages(). Hence pass
NULL instead of gather to iommu_v1_unmap_pages.
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20220825063939.8360-4-vasant.hegde@amd.comSigned-off-by: Joerg Roedel <jroedel@suse.de>