iommu/vt-d: Handle PCI bridge RMRR device scopes in intel_iommu_get_resv_regions

In the case the RMRR device scope is a PCI-PCI bridge, let's check
the device belongs to the PCI sub-hierarchy.

Fixes: 0659b8dc ("iommu/vt-d: Implement reserved region get/put callbacks")
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Reviewed-by: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -5426,7 +5426,8 @@ static void intel_iommu_get_resv_regions(struct device *device,
 			struct iommu_resv_region *resv;
 			size_t length;
 
-			if (i_dev != device)
+			if (i_dev != device &&
+			    !is_downstream_to_pci_bridge(device, i_dev))
 				continue;
 
 			length = rmrr->end_address - rmrr->base_address + 1;