Fix io_u depth array size

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/fio.h b/fio.h
index 28104cd..c2a0d4d 100644
--- a/fio.h
+++ b/fio.h
@@ -71,7 +71,7 @@
 /*
  * How many depth levels to log
  */
-#define FIO_IO_U_MAP_NR	8
+#define FIO_IO_U_MAP_NR	7
 #define FIO_IO_U_LAT_U_NR 10
 #define FIO_IO_U_LAT_M_NR 12