mtd/dataflash.c: fix a problem with the last partition

This patch fix the problem that only the [NB_DATAFLASH_AREA - 1] dataflash
partition can be defined to use the area to the end of dataflash size.
Now it is possible to have only one dataflash partition from 0 to the end
of of dataflash size.

Signed-off-by: Ilko Iliev <iliev@ronetix.at>
diff --git a/drivers/mtd/dataflash.c b/drivers/mtd/dataflash.c
index 58be182..96cd395 100644
--- a/drivers/mtd/dataflash.c
+++ b/drivers/mtd/dataflash.c
@@ -131,7 +131,7 @@
 			break;
 		}
 		/* set the last area end to the dataflash size*/
-		area_list[NB_DATAFLASH_AREA - 1].end =
+		dataflash_info[i].end_address =
 				(dataflash_info[i].Device.pages_number *
 				dataflash_info[i].Device.pages_size) - 1;