iommu/vt-d: Enable Translation only if it was previously disabled

Do not touch the TE bit unless we know translation is
disabled.
Tested-by: ZhenHua Li <zhen-hual@hp.com>
Tested-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/intel-iommu.c

@@ -3204,7 +3204,9 @@ static int __init init_dmars(void)
 		if (ret)
 			goto free_iommu;
 
+		if (!translation_pre_enabled(iommu))
 			iommu_enable_translation(iommu);
+
 		iommu_disable_protect_mem_regions(iommu);
 	}