[Patch Part1 V2 05/20] iommu/vt-d, trivial: refine support of 64bit guest address

In Intel IOMMU driver, it calculate page table level from adjusted guest address width as 'level = (agaw - 30) / 9', which assumes (agaw -30) could be divided by 9. On the other hand, 64bit is a valid agaw and (64 - 30) can't be divided by 9, so it needs special handling. This patch enhances

[Patch Part1 V2 05/20] iommu/vt-d, trivial: refine support of 64bit guest address

In Intel IOMMU driver, it calculate page table level from adjusted guest address width as 'level = (agaw - 30) / 9', which assumes (agaw -30) could be divided by 9. On the other hand, 64bit is a valid agaw and (64 - 30) can't be divided by 9, so it needs special handling. This patch enhances