iommu/omap: announce supported page sizes

Let the IOMMU core know we support 4KiB, 64KiB, 1MiB and 16MiB page sizes.

This way the IOMMU core can split any arbitrary-sized physically
contiguous regions (that it needs to map) as needed.

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Cc: Hiroshi DOYU <hdoyu@nvidia.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>