iommu/vt-d: Enable upto 57 bits of domain address width

Update the IOMMU default domain address width to 57 bits. This would
enable the IOMMU to do upto 5-levels of paging for second level
translations - IOVA translation requests without PASID.

Even though the maximum supported address width is being increased to
57, __iommu_calculate_agaw() would set the actual supported address
width to the maximum support available in IOMMU hardware.

Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>