corenet_ds: Extend board specific parameters

Extend board specific parameters to include cpo, write leveling override
Extend write leveling sample to 0xf
Adding rcw overrid for quad-rank RDIMMs

Signed-off-by: York Sun <yorksun@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

arch/powerpc/include/asm/fsl_ddr_sdram.h

diff --git a/arch/powerpc/include/asm/fsl_ddr_sdram.h b/arch/powerpc/include/asm/fsl_ddr_sdram.h
index e6f0d32..852e5c3 100644
--- a/arch/powerpc/include/asm/fsl_ddr_sdram.h
+++ b/arch/powerpc/include/asm/fsl_ddr_sdram.h
@@ -120,6 +120,9 @@
 #define MD_CNTL_WRCW		0x00080000
 #define MD_CNTL_MD_VALUE(x)	(x & 0x0000FFFF)
 
+/* DDR_CDR1 */
+#define DDR_CDR1_DHC_EN	0x80000000
+
 /* Record of register values computed */
 typedef struct fsl_ddr_cfg_regs_s {
 	struct {