iommu/vt-d: No need to typecast

Page directory assignment by alloc_pgtable_page() or phys_to_virt()
doesn't need typecasting as both routines return void*. Hence, remove
typecasting from both the calls.

Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210530075053.264218-1-parav@nvidia.com
Link: https://lore.kernel.org/r/20210610020115.1637656-24-baolu.lu@linux.intel.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>