Commit 2f26e0a9 ("iommu/vt-d: Add basic SVM PASID support") added a
special treatment to mandate that no page faults may be outstanding for
the PASID after intel_svm_unbind_mm() is called, as the PASID will be
released and reused after unbind.

This is unnecessary anymore as no outstanding page faults have been
ensured in the driver's remove_dev_pasid path:

- Tear down the pasid entry, which guarantees that new page faults for
  the PASID will be rejected by the iommu hardware.
- All outstanding page faults have been responded to.
- All hardware pending faults are drained in intel_drain_pasid_prq().

Remove this unnecessary code.
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
Link: https://lore.kernel.org/r/20240219125723.1645703-2-tina.zhang@intel.comSigned-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>