ide: save the returned value of dma_map_sg

dma_map_sg could return a value different to 'nents' argument of
dma_map_sg so the ide stack needs to save it for the later usage
(e.g. for_each_sg).

The ide stack also needs to save the original sg_nents value for
pci_unmap_sg.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
[bart: backport to Linus' tree]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/include/linux/ide.h b/include/linux/ide.h
index e0cedfe..25087ae 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -797,6 +797,7 @@
 	struct scatterlist *sg_table;
 	int sg_max_nents;		/* Maximum number of entries in it */
 	int sg_nents;			/* Current number of entries in it */
+	int orig_sg_nents;
 	int sg_dma_direction;		/* dma transfer direction */
 
 	/* data phase of the active command (currently only valid for PIO/DMA) */