iommu/vt-d: Match segment number when searching for dev_iotlb capable devices

For virtual machine and static identity domains, there may be devices
from different PCI segments associated with the same domain.
So function iommu_support_dev_iotlb() should also match PCI segment
number (iommu unit) when searching for dev_iotlb capable devices.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 3664d0d..147ab1c 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1272,7 +1272,8 @@
 
 	spin_lock_irqsave(&device_domain_lock, flags);
 	list_for_each_entry(info, &domain->devices, link)
-		if (info->bus == bus && info->devfn == devfn) {
+		if (info->iommu == iommu && info->bus == bus &&
+		    info->devfn == devfn) {
 			found = 1;
 			break;
 		}