iommu: add iommu_device_max_index IOMMU helper function

This function helps IOMMUs to know the highest address that a device
can access to.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
1 file changed