Prepare for supporting INFRA_IOMMU, and APU_IOMMU later.
For Infra IOMMU/APU IOMMU, it doesn't have the "larb""port". thus, Use
the MM flag contain the MM_IOMMU special flow, Also, it moves a big
chunk code about parsing the mediatek,larbs into a function, this is
only needed for MM IOMMU. and all the current SoC are MM_IOMMU.
Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>