amd-iommu: don't preallocate page tables with CONFIG_IOMMU_STRESS

This forces testing of on-demand page table allocation code.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 543822b..33434c4 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -661,6 +661,10 @@
 	int index = dma_dom->aperture_size >> APERTURE_RANGE_SHIFT;
 	int i;
 
+#ifdef CONFIG_IOMMU_STRESS
+	populate = false;
+#endif
+
 	if (index >= APERTURE_MAX_RANGES)
 		return -ENOMEM;