fsl-ddr: add the override for write leveling

add the override for write leveling sampling and
start time according to specific board.

Signed-off-by: Dave Liu <daveliu@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/include/asm-ppc/fsl_ddr_sdram.h b/include/asm-ppc/fsl_ddr_sdram.h
index 69b857b..15ab675 100644
--- a/include/asm-ppc/fsl_ddr_sdram.h
+++ b/include/asm-ppc/fsl_ddr_sdram.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2008 Freescale Semiconductor, Inc.
+ * Copyright 2008-2009 Freescale Semiconductor, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -177,6 +177,11 @@
 	unsigned int clk_adjust;		/* */
 	unsigned int cpo_override;
 	unsigned int write_data_delay;		/* DQS adjust */
+
+	unsigned int wrlvl_override;
+	unsigned int wrlvl_sample;		/* Write leveling */
+	unsigned int wrlvl_start;
+
 	unsigned int half_strength_driver_enable;
 	unsigned int twoT_en;
 	unsigned int threeT_en;