[SG] Update drivers to use sg helpers

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/scsi/NCR53c406a.c b/drivers/scsi/NCR53c406a.c
index 3168a17..137d065 100644
--- a/drivers/scsi/NCR53c406a.c
+++ b/drivers/scsi/NCR53c406a.c
@@ -875,8 +875,7 @@
 			outb(TRANSFER_INFO | DMA_OP, CMD_REG);
 #if USE_PIO
                         scsi_for_each_sg(current_SC, sg, scsi_sg_count(current_SC), i) {
-                                NCR53c406a_pio_write(page_address(sg->page) + sg->offset,
-                                                     sg->length);
+                                NCR53c406a_pio_write(sg_virt(sg), sg->length);
                         }
 			REG0;
 #endif				/* USE_PIO */
@@ -897,8 +896,7 @@
 			outb(TRANSFER_INFO | DMA_OP, CMD_REG);
 #if USE_PIO
                         scsi_for_each_sg(current_SC, sg, scsi_sg_count(current_SC), i) {
-                                NCR53c406a_pio_read(page_address(sg->page) + sg->offset,
-                                                    sg->length);
+                                NCR53c406a_pio_read(sg_virt(sg), sg->length);
                         }
 			REG0;
 #endif				/* USE_PIO */