Update arch/ to use sg helpers

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/arch/alpha/kernel/pci_iommu.c b/arch/alpha/kernel/pci_iommu.c
index e1c4707..ee07dce 100644
--- a/arch/alpha/kernel/pci_iommu.c
+++ b/arch/alpha/kernel/pci_iommu.c
@@ -465,7 +465,7 @@
    Write dma_length of each leader with the combined lengths of
    the mergable followers.  */
 
-#define SG_ENT_VIRT_ADDRESS(SG) (page_address((SG)->page) + (SG)->offset)
+#define SG_ENT_VIRT_ADDRESS(SG) (sg_virt((SG)))
 #define SG_ENT_PHYS_ADDRESS(SG) __pa(SG_ENT_VIRT_ADDRESS(SG))
 
 static void