[SG] Update drivers to use sg helpers

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/scsi/gdth.c b/drivers/scsi/gdth.c
index 3ac080e..5ab3ce7 100644
--- a/drivers/scsi/gdth.c
+++ b/drivers/scsi/gdth.c
@@ -2374,18 +2374,18 @@
             if (cpsum+cpnow > cpcount) 
                 cpnow = cpcount - cpsum;
             cpsum += cpnow;
-            if (!sl->page) {
+            if (!sg_page(sl)) {
                 printk("GDT-HA %d: invalid sc/gt element in gdth_copy_internal_data()\n",
                        ha->hanum);
                 return;
             }
             local_irq_save(flags);
-            address = kmap_atomic(sl->page, KM_BIO_SRC_IRQ) + sl->offset;
+            address = kmap_atomic(sg_page(sl), KM_BIO_SRC_IRQ) + sl->offset;
             if (to_buffer)
                 memcpy(buffer, address, cpnow);
             else
                 memcpy(address, buffer, cpnow);
-            flush_dcache_page(sl->page);
+            flush_dcache_page(sg_page(sl));
             kunmap_atomic(address, KM_BIO_SRC_IRQ);
             local_irq_restore(flags);
             if (cpsum == cpcount)