iommu/vt-d: Use pasid_pte_is_present() helper function

iommu/vt-d: Use pasid_pte_is_present() helper function

Use the pasid_pte_is_present() helper for present bit check in the
intel_pasid_tear_down_entry().

Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20210817042425.1784279-1-yi.l.liu@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210818134852.1847070-9-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>