vtd: Require unmap_vtd_domain_page() on a couple of early exit paths.

From: Jan Beulich <JBeulich@novell.com>
Signed-off-by: Keir Fraser <keir@xen.org>
xen-unstable changeset:   22549:aa18b8ddaf05
xen-unstable date:        Thu Dec 16 15:38:57 2010 +0000

xen/drivers/passthrough/vtd/iommu.c

@@ -1300,6 +1300,7 @@ static int domain_context_mapping_one(
     if ( context_set_domain_id(context, domain, iommu) )
     {
         spin_unlock(&iommu->lock);
+        unmap_vtd_domain_page(context_entries);
         return -EFAULT;
     }
 
@@ -1631,6 +1632,7 @@ static int intel_iommu_map_page(
     if ( old.val == new.val )
     {
         spin_unlock(&hd->mapping_lock);
+        unmap_vtd_domain_page(page);
         return 0;
     }
     *pte = new;