IOMMU/x86: drop TLB flushes from quarantine_init() hooks

The page tables just created aren't hooked up yet anywhere, so there's
nothing that could be present in any TLB, and hence nothing to flush.
Dropping this flush is, at least on the VT-d side, a prereq to per-
device domain ID use when quarantining devices, as dom_io isn't going
to be assigned a DID anymore: The warning in get_iommu_did() would
trigger.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>

xen/drivers/passthrough/amd/iommu_map.c

@@ -656,8 +656,6 @@ int __init cf_check amd_iommu_quarantine_init(struct domain *d)
  out:
     spin_unlock(&hd->arch.mapping_lock);
 
-    amd_iommu_flush_all_pages(d);
-
     /* Pages leaked in failure case */
     return level ? -ENOMEM : 0;
 }

xen/drivers/passthrough/vtd/iommu.c

@@ -2975,9 +2975,6 @@ static int __init cf_check intel_iommu_quarantine_init(struct domain *d)
  out:
     spin_unlock(&hd->arch.mapping_lock);
 
-    if ( !rc )
-        rc = iommu_flush_iotlb_all(d);
-
     /* Pages may be leaked in failure case */
     return rc;
 }